acdream/docs/plans/2026-08-02-placement-cutover.md

# Placement production cutover — campaign plan (2026-08-02)

The final leg of the remaining physics-divergence campaign before AP-22 and
AD-10: route graphical AND headless production placement through the
residence + continuation-executor owner (`38fd4b8d` / `30012361` /
`5db3de3c`), delete the legacy duplicate authorities, and retire AP-1/AD-1
behind connected + user-visual gates.

## Handoff checkpoint — 2026-08-03

**Status: stabilization checkpoint accepted; campaign closeout is not yet
complete.** The C3c production cutover and the O(changed) collision
publication checkpoint are now playable after five separately committed
root-cause fixes:

- `01f4791e` stops origin recenter from manufacturing and replaying a second
  retirement receipt for a pending-only live-projection bucket. Its exact
  binary passed the complete Release suite, lifecycle route, and canonical
  nine-stop soak (`connected-r6-soak-20260802-204309`, nine stops, zero
  failures/wait cues/pending retirements).
- `670f307c` keeps remote Create placement, the local-player physics host,
  targeting, chasing, and attacks in the same world-coordinate frame. The
  user accepted monster placement/chase/hit behavior and static placement
  after portals.
- `1fc529cd` materializes the canonical minimal static physics host before a
  distant Use/MoveTo route and reconciles the pre-PartArray startup motion
  suffix. The user accepted near and distant object use.
- `f24532ad` defers one-shot F754/F755 effects until canonical placement has
  bound presentation, retries projectile/static-animation sidecars on the
  committed visibility edge, and keeps effect cells synchronized. The user
  accepted buffs, recalls, arrows, combat spell projectiles, portals, and
  static animation.
- `175ad6b0` sends LoginComplete from the local first-placement terminal edge
  instead of raw PlayerCreate receipt, so ACE's intentional login Hidden/
  materialization state cannot race placement. The user accepted the login
  haze behavior.

Focused verification after the final fix passed 90 App effect/projectile/
static-scheduler tests, two Runtime login tests, the exact live-entity cell
tracking regression, all 79 Headless tests, and the Release solution build
with zero errors. The long connected soak and complete solution suite have
**not** been rerun on the final `175ad6b0` binary. A broader selected fixture
run also exposed five `LiveEntityRuntimeTests` failures tied to the still-open
placement cutover plus one old remote first-entry fixture that supplies an
empty collision source; classify and fix those before claiming C5 closure.

Remaining campaign work, in order:

1. Reproduce and repair the six fixture failures without weakening their
   assertions or adding compatibility bypasses.
2. Finish C4's routes 2–7 and remove their legacy placement writers; fold in
   #276 and #277 where their route becomes authoritative.
3. Resolve #280 with retail's configured destination-prefetch window so the
   portal viewport never reveals visibly constructing far terrain.
4. Run C5's complete Release suite, lifecycle/reconnect route, latest-binary
   nine-stop soak, two-client observation, and the remaining #269 slope-glide
   visual check. A pass from `01f4791e` is evidence for that fix, not a
   substitute for the final-binary soak.
5. Delete the superseded paths, retire AP-1/AD-1/AP-131 and AD-60's legacy
   half only when the code proves they are gone, then complete AP-22 and
   AD-10 and close the campaign ledger.

**Inputs (read in order):**
1. [`2026-08-02-runtime-continuation-executor-handoff.md`](../research/2026-08-02-runtime-continuation-executor-handoff.md)
   — the completed dormant mechanism and its cutover notes.
2. [`2026-08-02-cutover-route-inventory.md`](../research/2026-08-02-cutover-route-inventory.md)
   — the full 8-route, both-host call-chain inventory with exact file:line
   for every duplicate authority to remove. THE map for all slices below.
3. [`2026-07-31-remaining-physics-campaign-handoff.md`](../research/2026-07-31-remaining-physics-campaign-handoff.md)
   — the original per-route requirements and prerequisite definitions.

**Standing discipline per slice:** pinned contract → single implementer →
independent retail-conformance + architecture/adversarial reviews (both must
PASS on the final diff) → focused + complete Runtime + Release build +
complete solution gates → bisectable behavior commit (register rows in the
same commit) → docs/handoff commit. No workarounds; no fused slices.

## Confirmed pre-cutover gaps (from the inventory)

- The executor publishes only generic entity deltas; nothing bridges its
  completion to `RuntimePlacementProjectionChannel`, so no host can learn
  "my initial placement committed" through the built observer seam.
- No atomic controller/body publication owner exists (prerequisite C);
  App and headless hand-write divergent `PlayerMovementController`
  construction, and `SubmitPreparedPlacement` requires a canonical
  `PhysicsBody` that nothing currently publishes atomically.
- The dormant placement path's 1,880 B/operation (2,048 cap) allocation
  remains the activation blocker for frame-frequency routes.
- `Execute`'s live inputs (`UsePositionFromServer`, `PlayerDistance`) are
  computed by no host; they must derive from Runtime's own character-option
  and local-player owners.
- `RuntimePortalPlacementAuthority` has zero producing call sites; the
  adapter from `RuntimeWorldTransitState` does not exist.
- The exact-Setup mover chain (`PrepareMover` /
  `RuntimeSetPositionMoverPreparer.TryBuild` /
  `IPreparedCollisionSource.ReadSetupCollision`) exists piecewise, unwired.
- **Corrected 2026-08-04 (C4 route 6 closure,
  `docs/research/2026-08-04-c4-route-6-contract.md`): all three clauses
  above were stale.** Route-6 split-recovery does NOT need an effect-replay
  suppression signal — that premise was unsubstantiated; acdream's only
  create-time effect replay is the F754/F755 queue drain keyed by server
  GUID, and the one plausible mechanism (a cloned `DefaultScriptType`
  surviving `BuildSpawn`) never fires at create in either client
  (`CPhysicsObj::play_default_script @0x005132B0`/`@0x00513300` has exactly
  two callers, both animation hooks, verified against
  `acclient_2013_pseudo_c.txt`). Route-7's `TryCommitParent`/
  `CommitWithdrawal` cancellation-symmetry fixes and host-visible
  cancellation receipts were BOTH closed at C0 (see the C0 slice below).
  What actually remains for route 7: the child's canonical cell has two
  writers (Runtime commits it cell-less unconditionally in
  `CommitAcceptedParentCellless`, while `EquippedChildRenderController
  .TickChild` re-cells it from a per-frame render tick), and headless has no
  `EquippedChildRenderController` at all, so every headless parented child
  stays cell-less forever — the same defect seen from two sides, not two
  separate gaps.

## Slices

- **C0 — Runtime bridge + live inputs — COMPLETE at `67f63e85`
  (2026-08-02, dual reviews PASS).** The executor publishes an
  acknowledge-only `ExecutorCompleted` receipt through the one placement
  stream (registered before dispatch; correlation reaped on
  acknowledgement/discard/clear; `PendingCompletionReceiptCount` in
  `IsConverged`); all three production sinks acknowledge-and-ignore the
  kind via early returns proven behavior-preserving for every other kind
  (sanctioned seam completion — provably inert, no production publisher);
  `UsePositionFromServer` derives retail-exactly from
  `RuntimeCharacterState.AutonomyLevel != 2` and `PlayerDistance` from the
  live movement controller with null-safe fallback to the caller struct;
  `TryPrepareAndSubmitAuthoredPlacement` chains the prepared-collision
  Setup read through `PrepareMover` to submission with zero validation
  changes; `TryCommitParent`/`CommitWithdrawal` gained the sibling
  cancellation flow (the `LeaveWorld` omission in `TryCommitParent` is
  retail-REQUIRED per `set_parent` 0x00515A90:283832-283833's single gated
  `leave_world`). Not fully dormant by design: the two cancellation fixes
  change live Runtime paths production already calls; everything else has
  no production caller.
  **C3 prerequisites recorded from C0's reviews:** (a) the completion
  receipt/trace surface is internal-only — C3 must define the public host
  consumption shape when it wires the hosts; (b) `PlayerDistance` is
  resolved once per `Execute` entry, not per continuation — a multi-Position
  FIFO classifies later entries against entry-time distance (documented
  deferral; refine at C3/C4 if the connected gates show it matters);
  (c) any future host exposure of `TrySetAutonomyLevel` must carry retail's
  `SendAutonomyLevelEvent` (699550).
- **C1 — atomic controller/body publication — SATISFIED BY EXISTING
  MECHANISM (research finding 2026-08-02, plan amended same session).**
  `RuntimeLocalPlayerPhysicsPublicationState` (1,033 lines) plus the
  ~15-method dormant local-activation family on `RuntimeSetPositionState`
  already implement the full sanctioned option-2 transaction:
  off-canonical preparation against a scratch quantum clock and a sealed
  candidate controller, one validated atomic Commit, and a staged
  Evaluate/Commit/FinalizeActivation chain re-validated against
  PhysicsOwnershipEpoch/ObjectClockEpoch/ControllerOwnershipEpoch/session
  identity at every entry — with zero production callers. See
  [`2026-08-02-canonical-body-writer-map.md`](../research/2026-08-02-canonical-body-writer-map.md)
  (6 canonical body writers; the two host escape hatches; both hosts'
  divergences). The remaining work — routing both hosts' local-player
  construction through the publication lifecycle, sealing the public
  `RuntimeLocalPlayerMovementState.Controller` setter, retiring App's
  direct object-clock bypasses, and containing headless's uncaught
  prepared-collision `InvalidDataException` — IS the C3 route-1 flip and
  moves there. No separate C1 commit.
- **C2 — placement allocation budget — COMPLETE at `63c601ff`
  (2026-08-02, dual reviews PASS after two fix rounds).** 2,032 → 944
  B/op via pooled operation envelopes (bounded, reset-at-rent, double-
  retire guarded, reset/dispose-cleared, ledger-visible), a cached
  collision-callback delegate over an explicit context stack, and a
  non-boxing pending-head read; gate tightened to 1,536. The pooling
  forced a class-wide staleness rework: captured-token-vs-fresh-lookup at
  every reentrancy-spanning frame (26-site audit), hoisted stack locals
  for retail's handle_all_collisions bits, token-gated bookkeeping
  writes, and a deliberately identity-agnostic settle path (retail's
  SetPositionInternal completes unconditionally even for displaced
  operations).
  **Residual floor (documented at the gate, decision deferred to the C3
  activation gate where the user is in the loop):** ~520 B/op inside
  Core's `PhysicsEngine.SetPosition` (transition init / query-footprint
  materialization — a potential C2b if C3's connected profile shows it
  matters) and ~208 B/op of sorted-tree node per pending receipt.
  **Maintenance notes from review (no action):** the no-reentrancy
  proofs on the 15 surviving reference-based currency checks are
  comment-enforced; `IsCurrent(Operation)` remains available and a new
  reentrancy-spanning call site would silently inherit the tautology —
  its doc comment warns.
- **C3 — spawn-frequency cutover: routes 1 + 8 — DECOMPOSED 2026-08-02
  after the first implementation pass stopped with findings.** C3-1 (the
  public executor-completion surface via
  `RuntimePlacementProjectionChannel.TryGetInitialCreateCompletion`)
  landed separately. Two structural gaps halted the flip, both real and
  neither in the planning docs:
  **(B)** the local player's residence lease opens its SetPosition
  operation at Create time, but `SubmitPreparedPlacementCore` requires a
  pre-existing canonical body that only the zero-caller publication chain
  can attach — first-entry needs an explicit resumable sequence
  (begin-placement → publication Prepare/Commit attaches the body →
  authored-mover submit → Place receipt → Execute), which matches the
  campaign handoff's route-1 required order but exists nowhere as a
  driveable state machine;
  **(C)** ordinary remote-creature Creates classify to `SetPosition` but
  have NO production body-construction path at Create time (bodies arrive
  with first motion today; retail constructs physics at CreateObject via
  `ACCObjectMaint::CreateObject`/`set_description`, which our retail
  notes fully document — the defaults come from the wire PhysicsDesc,
  not invention).
  Sub-slices, each with the standing contract/dual-review/gate
  discipline:
  - **C3a — Runtime first-entry sequencing — COMPLETE at `960373df`
    (2026-08-02, dual reviews PASS).** `RuntimeLocalPlayerFirstEntryState`:
    five stages (mover-prep → publication Prepare/Commit → activation →
    acknowledgement → Execute) in retail's own order — mover shapes
    BEFORE placement, matching makeObject/set_description preceding
    enter_world; the original contract prose had it backwards and the
    tested preconditions forced the faithful order. Acknowledge-stage
    authority discrimination, automatic convergence through the (now
    multicast, snapshot-iterated) retirement fan-out, ownership-ledger
    fold, transactional late-bind Publication seam. Dormant: C3c's first
    act is the GameRuntime binding + production Advance drive.
    **Carried findings for C3c:** the controller is live from the
    activation commit onward (abandonment leaves it to ordinary entity
    teardown — retail has no entry-flow rollback); EvaluateActivation's
    post-commit DeferredCell overload is encapsulated behind Advance.
  - **C3b — remote body construction at Create — COMPLETE at `0934a121`
    (2026-08-02, dual reviews PASS).** `RuntimeRemoteBodyDescription` +
    `RuntimeRemoteFirstEntryState`: the full `set_description` order with
    the byte-certain gates (friction [0,1] inclusive, NaN sanctioned-skip;
    elasticity clamp with retail's unordered-to-zero; translucency
    != 0.0f), the movement-branch discriminator on retail's
    `movement_buffer != 0` (empty-buffer → placement branch, no autonomy),
    motion-table zero-id pass, ctor-defaults for absent wire fields, and
    never-clobber coexistence with the build-at-first-motion production
    path. The acknowledge discriminator is one shared body
    (`RuntimeFirstEntryAcknowledgement`) for both conductors. Dormant.
  - **C3c — the host flips (production) — COMPLETE at `529e0e9d`
    (2026-08-02, dual Opus reviews: initial FAIL 2+2 MAJOR → R1 fix
    round → delta PASS both).** Both hosts register initial Creates
    through residence + conductors via the shared
    `RuntimeFirstEntryDriveController`; Controller setter sealed;
    rebucketing presentation-only strictly while the residence is
    ACTIVE (post-residence entities take the full legacy path including
    the `prepare_to_enter_world` clock edges); content-less headless
    keeps pre-flip direct registration. Five fix slices landed inside
    the cutover, each connected-gated: F1 (Runtime ownership seam for
    movement stats/server physics — the post-logout retired-controller
    crash), F2 (the login activation wedge: admission-prefix gate
    factored from the seal, rearm generation identity, auto-entry
    requires the published controller), F3 (landblock-prefix 0-sentinel
    → explicit absent-id; corner landblocks legal), F4 (diagnosis only:
    the nine-stop soak's convergence failure is pre-existing `6b28ff99`
    whole-world collision-clone throughput — its fix is the next slice
    before C5), F5 (local-player first-entry ground contact via the
    shared `SpawnPlacementSettler` at `FinalizeActivation`; the
    standing-cast airborne rejections are gone; register AD-61). R1
    additionally armed the login constraint leash at the committed
    placement (`HandleReceivedPosition` 0x00453FD0 analog) and
    refreshed AD-42. Final gates: complete solution 10,816/0/4 skips;
    lifecycle/reconnect gate PASS (`connected-world-gate-20260802-
    175401`). Closeout:
    [`2026-08-02-c3c-cutover-closeout.md`](../research/2026-08-02-c3c-cutover-closeout.md).
    **Carried to C4/C5:** route-1 far-Create service-window conversion
    if either streaming/broadcast radius changes (#277); the
    window-departure park narrowing; `NotifyRetirement`-on-active-entry
    subscriber invariant; the reachable equip-mid-conductor fail-fast;
    settle-CellId discard (#276-adjacent, see ISSUES).
- **C4 — remaining routes: 2 (ForcePosition), 3 (portal, with the
  `RuntimeWorldTransitState` → `RuntimePortalPlacementAuthority` adapter),
  4 (remote Create/Position; delete `RemoteTeleportController`/`Placement`
  and the inline MoveOrTeleport duplicate), 5 (projectile authoritative),
  6 (drops + split-recovery marking), 7 (residual pickup/parent/delete
  polish). — route 2 COMPLETE AND USER-ACCEPTED 2026-08-03 (`9966b531`);
  routes 3/4/5/6/7 remain OPEN.**
  **Route 4 SPLIT into 4a and 4b (user-directed 2026-08-03).** Scoping
  ([`2026-08-03-c4-route-4-scoping.md`](../research/2026-08-03-c4-route-4-scoping.md))
  put whole-route 4 at 1,500-2,500 production lines against a stated ~400
  budget, so it is split to keep each landing reviewable:
  - **4a — the steady state.** The classifier's `Interpolate` (contact,
    `PlayerDistance < 96 m`) and `NoPositionOperation` (no contact) branches.
    NEITHER runs a `SetPosition`, so 4a has no deferred-cell park, no
    service-window work, and no placement-allocation exposure. Fixes two of the
    three unfiled divergences (the NPC airborne hard-snap that ignores the wire
    `IsGrounded` bit; `ConstrainTo` armed before the operation instead of
    after). Highest visible value — this is what makes creatures move smoothly.
  - **4b — the edges.** `SetPosition` / `SetPositionSimple`: teleport, far-snap
    (>= 96 m), and cell-less first placement. This is where the parks, the
    Position-time service-window guard, #277's broken bound, N3 (headless never
    calls `RetryPending`), and the third divergence (`ConstrainTo` never armed
    on the remote teleport branch) all live.

    **4b also inherits 4a's ownership remainder — scheduled here, not implied
    by code comments.** Two independent reviews flagged that 4a satisfies
    contract items 1 and 2 only partially, and the plan must carry that rather
    than leaving it in `// 4b deletes this fallback` comments:
    - Runtime owns the classification, the request construction (one shared
      builder, `RuntimeAcceptedPositionRouteRequests`), the near-InterpolateTo
      decision with AP-87, and the post-operation `ConstrainTo`. **App still
      owns** branch selection, the airborne early return, the
      `RemoteMotion.CellId` write, the `WorldEntity` pose write, and the
      collision-shadow publish — all in `LiveEntityNetworkUpdateController`.
    - Item 2 ("both hosts drive the identical Runtime entry point") is
      satisfied only VACUOUSLY: `RuntimeLiveEntitySessionController` returns
      early for remotes, so no no-window host exercises this path at all and
      nothing can diverge yet. That stops being true the moment a headless
      host needs remote motion.
    - Every legacy fallback 4a deliberately left in place is 4b's to delete:
      the pre-operation unconditional `ConstrainTo`, the player arm's
      `!update.IsGrounded` no-op, the player and NPC legacy near/far routing
      (each still carrying its own duplicate `96f` / `4f` constants), and the
      airborne-precedence carve-out
      (`LiveEntityNetworkUpdateController.ApplyRemoteContactRouting`) that
      keeps a landing body snapping. Retiring the last one is a real behaviour
      decision — retail makes no player/NPC distinction there — and needs its
      own live evidence, not a silent convergence.
    - Register row **AP-135** (the airborne no-op's retained acdream
      bookkeeping: the server cell id for the free-fall sweep gate, and the
      last-server-position sample) — **CORRECTED 2026-08-04: this row does NOT
      retire with 4b.** Its own stated condition is retirement together with the
      free-fall sweep gate (`RuntimeRemotePhysicsUpdater.cs:342`), which 4b does
      not touch, and its sites are the airborne no-op branches — 4a-owned
      dispositions, not 4b's far-snap/teleport/cell-less. The trap is that those
      two writes sit physically inside `OnPosition`, which 4b rewrites heavily,
      so an implementer will assume they go. They stay. See
      [`2026-08-04-c4-route-4b-scoping-and-split.md`](../research/2026-08-04-c4-route-4b-scoping-and-split.md).
    - **4b is itself split into 4b-1 / 4b-2 / 4b-3** (2026-08-04). Scoping put
      4b at 1,300-2,200 production lines — 4-6x route 4a — plus ~2,500-3,500
      lines of test work. 4b-1 is infrastructure with no remote behaviour change
      (the per-entity placement owner, the service-window guard, the
      refuse-rather-than-park policy, N3's headless `RetryPending` pump); 4b-2 is
      the far branch alone; 4b-3 is teleport/cell-less and the ~739-line class
      deletions. 4b-1 stays a separate landing regardless: it is where the
      park-withdraws-the-entity failure mode is decided, and it must not be
      reviewed alongside a large deletion.
    - **4b-2 LANDED at `7f1c1f5a` (2026-08-04); far-snap connected gate
      USER-PASSED same day.** Four fix rounds, eight Opus reviews; the slice was
      fully green at 10,990 / 10,997 / 11,004 while containing real defects
      (a frozen remote pinned as correct by its own test; a fallback that
      over-wrote on the exact retail paths that decline to store; a park guard
      incomplete on two independent axes). Final suite 11,009 / 4 / 0 against a
      **measured** 10,968 baseline — the 10,973 figure used earlier was wrong.
      Its real yield was a defect under routes 1 and 2, not the far snap:
      `ParkDeferred`'s quiescence parks withdrew the entity and were never
      restorable while `Forget(restoreCancelledPark: true)` runs for every
      accepted Position on every entity. The restorable decision now lives
      inside `ParkDeferred` after `SnapToCell`, read against every live
      quiescence.
      **Still outstanding: #309.** The `ACDREAM_PROBE_PARK=1` capture from the
      accepting session shows 11 parks, all `cause=unplaceable` — zero
      quiescence-cause parks, so the shared-core park change is NOT yet
      connected-verified. Without the probe that session would have been
      recorded as a pass.
      Process lesson recorded: the round-1 defect was caused by the contract
      omitting "and still advance the pose", and the park defect should have
      been split into its own slice the moment it surfaced in round 2 instead
      of riding inside 4b-2 for three more rounds.
      Findings chain:
      [contract](../research/2026-08-04-c4-route-4b-2-contract.md) →
      [round 1](../research/2026-08-04-c4-route-4b-2-review-findings.md) →
      [round 2](../research/2026-08-04-c4-route-4b-2-delta-review-findings.md) →
      [round 3](../research/2026-08-04-c4-route-4b-2-round3-correction.md) →
      [round 4](../research/2026-08-04-c4-route-4b-2-round4-correction.md).
  Note the route-4 Create half is ALREADY DONE (C3b/C3c); the remaining work is
  steady-state remote Position plus the deletions. AP-131 is NOT retired by
  either sub-slice — see the scoping doc for why route 4 alone cannot.
  4a contract: [`2026-08-03-c4-route-4a-contract.md`](../research/2026-08-03-c4-route-4a-contract.md).
  **Route 2 connected gate PASSED (user, 2026-08-03).** Provoked with the
  retail `@pklite` entry-collision bump (`69ba9486` — the only reachable ACE
  trigger for `ObjectForcePosition`; admin teleports advance `ObjectTeleport`
  and exercise route 3 instead, see
  [`2026-08-03-c4-route-2-visual-gate.md`](../research/2026-08-03-c4-route-2-visual-gate.md)).
  The user observed the visible slide off the overlapped character (the
  ForcePosition applied), correct animation, no heading change, and no leash
  tethering or rubber-band after the correction — so the two named behaviour
  changes (ack after commit; no `ConstrainTo` re-arm on this route) are
  accepted live. Both Opus reviews PASS on the final diff after three FAIL
  rounds.
  **Adjacent, NOT a route 2 regression:** shipping `@pklite` made PK Lite
  reachable for the first time and immediately exposed pre-existing PvP gaps —
  melee/ranged attacks refuse a PKLite target (auto-target retargets to the
  nearest other; auto-target off does nothing) while spells on the same target
  work. Under investigation; filed separately.
  **Route 2 (ForcePosition) — implemented 2026-08-03, contract:**
  [`2026-08-03-c4-route-2-contract.md`](../research/2026-08-03-c4-route-2-contract.md),
  **plan:** [`2026-08-03-c4-route-2-implementation-plan.md`](../research/2026-08-03-c4-route-2-implementation-plan.md).
  `RuntimeAcceptedPositionDriveController`
  (`src/AcDream.Runtime/Session/RuntimeAcceptedPositionDriveController.cs`)
  is the single accepted-Position execution seam for a ForcePosition on the
  already-live local player; `LocalForcePositionTransaction` and
  `HeadlessSessionWorldProjection.BlipLocalPlayer` are deleted, and the
  generic App render-tail is skipped for the local player's ForcePosition.
  Named behaviour changes (both retail-exact, ISSUES #285): the outbound
  ack now fires strictly after the canonical commit, and the constraint
  leash is no longer re-armed on this route (retail's FORCE_POSITION branch
  never reaches `ConstrainTo`).
  **Fix round (2026-08-03):** both independent dual reviews (retail-
  conformance + architecture/adversarial) FAILed the first pass — see
  [`2026-08-03-c4-route-2-review-findings.md`](../research/2026-08-03-c4-route-2-review-findings.md)
  for the full R1-R9 list. The critical finding (R1) was that the
  DeferredCell park could not survive a single ACE broadcast interval in
  production (`RuntimeEntityObjectLifetime.TryApplyPosition`'s unconditional
  `Forget` on every accepted Position cancelled it before its collision
  generation could commit), silently dropping the correction forever;
  `RuntimeAcceptedPositionDriveController.Advance` now detects the dead
  watch and re-issues from the entity's current canonical snapshot. R2/R3
  restored headless's collision re-centering and login-window fallback; R4
  stopped the force-ack from stealing a receipt the presentation sink had
  legitimately declined; R5/R6/R9 corrected false doc claims, closed a
  `_pending`-leak/overwrite gap, and fixed streaming-observer/pose-dirty
  side effects firing on a declined placement. R7 corrected a fixture bug
  (a dummy Setup sphere with its centre at the origin) that had been
  written up as a retail fidelity gain; R8 added App-layer double-write
  source pins and corrected an overclaimed single-ack test. Full detail:
  [`2026-08-03-c4-route-2-review-findings.md`](../research/2026-08-03-c4-route-2-review-findings.md).
  Complete Release solution after the fix round: **10,853 passed / 4
  skipped / 0 failed** (baseline 10,844/4/0; first pass 10,848/4/0).

  **Acceptance item 2 is NOT met — recorded gap, B2 (2026-08-03 round 2).**
  An earlier revision of this paragraph claimed R8 "added the App-layer
  double-write source pins the plan's own acceptance item required". That was
  a claim of coverage this changeset does not have, and it is corrected here
  rather than left as the citation a future session trusts (same rule that
  produced R7). The truth, per the adversarial review:
  - *First half — "the generic tail no longer double-writes the local
    player":* **source-pinned, not proven.** The pin is a regex/`Assert.Single`
    over `LiveEntityNetworkUpdateController`'s source text, so it would still
    pass if a second write were spelled differently, and **no test exercises
    the branch** at runtime.
  - *Second half — "the committed projection is what moves the render
    entity":* **uncovered at any layer.** No test drives a route-2
    ForcePosition through `RuntimePlacementPresentationSink` /
    `TryApplyRuntimePlacementPlace` and asserts the `WorldEntity` actually
    moved. Given R4 (the force-ack no longer consumes a declined `Place`),
    this is precisely the seam whose failure mode is silent: the canonical
    body moves and the render entity stays put.
  Closing this gap needs an App-layer test that runs the accepted
  ForcePosition end to end and asserts the render entity's position/cell came
  from the committed placement receipt — carry it into C5's parity tests or
  file it before this sub-landing closes.
  **Not yet done:** both reviews must be RE-RUN on this fixed diff, and the
  connected (user-gated) acceptance gate this campaign's standing
  discipline requires, before this sub-landing is considered closed — those,
  and the commit itself, are next. May land as more than one commit if a
  route proves large; each sub-landing keeps the full review discipline.
- **C5 — legacy deletion + closeout gates — OPEN.** Delete every superseded legacy
  path; parity tests; exact lifecycle/reconnect + canonical nine-stop
  connected routes; two-client observation; **user visual matrix** (the
  campaign's stopping point for user acceptance). Retire AP-1, AD-1,
  AP-131, AD-60's legacy half, and close #275. Update register/roadmap/
  milestones/architecture/memory + successor handoff.

After C5: AP-22 (authored collision shapes), then AD-10 (remote
contact-plane projection), then the campaign's final matrix and ledger
closeout; vendor Slice 5 resumes.