feat(net): N4 - client NAK emission + RejectRetransmit reclaim

Campaign N slice N4 completes the AckNakScheduler NAK branch and closes
the ACE cleartext-reject keystream hazard - the slice that makes S2C
loss actually RECOVER.

NAK emission (SharedNet::EnqueueNaks @ 0x00543BD0):
- One cleartext exact-flags RequestRetransmit per sweep behind the
  STRICT 0.6 s gate on the ONE shared timestamp (the x87 0x41-mask test
  at 0x00543C03 proceeds only on strictly-greater; the ack's gate stays
  >=). Never an ack in a NAK sweep; a NAK delays the next ack by 2.0 s
  and vice versa (landmine #7).
- Body = u32 count + ids ascending, capped at 114 (ReceiverData::GetNaks
  @ 0x005490C0, cap 0x72; the m_cbData = 4*count+4 store at 0x00543C3E);
  header Sequence borrowed from highestIDSent_ without incrementing;
  cleartext or ACE ignores it (landmine #6, NetworkSession.cs:283-284) -
  and a NAK never refreshes ACE's 60 s timeout.
- Control-header rule decided once for BOTH ack and NAK: Time = the
  interval id, Iteration = the session iteration, matching retail's
  shared header build (FlowQueue::TransmitNewPackets @ 0x00547A60, the
  stack build at 0x00547A84). ACE reads neither field inbound.
- Gate ticks now round instead of truncate: 0.6 has no exact double
  form, and truncation opened the strict gate exactly AT the boundary.

RejectRetransmit reclaim (divergence register AD-51, ACE adaptation):
- ACE's RejectRetransmit consumes a FRESH sequence, cleartext, with NO
  keystream word, and is cached (ACE NetworkSession.cs:299-304,
  :722-725, :743-748) - the one place ACE breaks retail's gap-walk
  invariant that every missing id was word-bearing (retail cleartext
  always borrows live sequences). Unhandled, the gap walk parks a word
  for the reject's id and the inbound stream runs permanently one word
  ahead - the N2 desync class reintroduced through the reject path.
- Fix: on a VALIDATED cleartext reject, InboundSequenceTracker removes
  the mis-park, shifts every later-drawn parked word down one position
  (per-word draw ordinals; ascending wrap-safe id <=> ascending draw
  order), and pools the excess word, consumed lowest-draw-order-first
  ahead of fresh ISAAC draws. Exact for any number of interleaved
  rejects in ANY arrival order - a plain reclaim FIFO is not: a reject
  arriving after a higher encrypted arrival crosses the parked chain,
  and two out-of-order rejects pool their excess words out of draw
  order (both orderings pinned by tests).
- Reject BODY ids keep N2's discard: word-bearing server-side,
  consumed-in-place. The pool is provably empty against retail servers.

N3 advisories folded (all five): honest transitional-state wording (the
empty N3 NAK branch could silently disconnect a loopback session at
ACE's 60 s timeout, witness [net-tick] acks/s=0), the
ReceiverData::SharedInit @ 0x00548EF0 (from Init @ 0x00548FA0)
citation, the FlowQueue::Empty pump-order wording (TransmitNaks ->
TransmitAcks -> TransmitNewPackets with the interval increment LAST @
0x00548A9D; our clock-first Sweep is cosmetic vs ACE), the
Time/Iteration rule above, and the stale WorldSession budget-break
comment rewritten to the sweep reality.

Tests: 737 Core.Net green (14 new in NakEmissionTests + updated N3
pins): strict-gate boundary, shared timestamp both directions,
NAK-xor-ack exclusivity, full wire-shape + 114-cap pins, model-served
retransmission round trip, five tracker reclaim proofs, the 130 s
virtual prune -> fresh-sequence reject system test (victim abandoned,
later traffic decodes, pool drains to zero), 10 s long-loss survival
(NAKs on the gate cadence, zero acks, heal inside the window), and the
capstone soak: 2% seeded bidirectional loss x 10,000 messages -> zero
message loss both ways, ACE crypto headroom 256 at convergence, every
ledger drained (cache at the single watermark entry - retail's Flush
prunes STRICTLY below the ack). Full solution Release: 9,758 passed /
5 skipped. Connected world-lifecycle gate PASS
(logs/connected-world-gate-20260729-150238); canonical nine-stop soak
PASS (logs/connected-r6-soak-20260729-150856).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/architecture/retail-divergence-register.md

@@ -62,7 +62,7 @@ accepted-divergence entries (#96, #49, #50).
 
 ---
 
-## 2. Adaptation (AD) — 42 rows (AD-50 filed 2026-07-29 at Campaign N slice N2 — the inbound-watermark ACE init; AD-49 stays reserved for Campaign N §5's blob-layer ordering deferral, filed when its slice lands; AD-47 and AD-48 filed 2026-07-29 at Campaign V slice V11 — the MSAA sample-position and present-pacing rows the campaign's risk register scheduled for the GL deletion; AD-11 retired 2026-07-23 — exact low-bit ItemUses predicate; AD-31 retired 2026-07-15 — the DAT-authored portal-space viewport replaces the black transit cover)
+## 2. Adaptation (AD) — 43 rows (AD-51 filed 2026-07-29 at Campaign N slice N4 — the reclaimed-word pool for ACE's fresh-sequence cleartext RejectRetransmit; AD-50 filed 2026-07-29 at Campaign N slice N2 — the inbound-watermark ACE init; AD-49 stays reserved for Campaign N §5's blob-layer ordering deferral, filed when its slice lands; AD-47 and AD-48 filed 2026-07-29 at Campaign V slice V11 — the MSAA sample-position and present-pacing rows the campaign's risk register scheduled for the GL deletion; AD-11 retired 2026-07-23 — exact low-bit ItemUses predicate; AD-31 retired 2026-07-15 — the DAT-authored portal-space viewport replaces the black transit cover)
 
 | # | Divergence | Where (file:line) | Why it is safe / justified | Risk if assumption breaks | Retail oracle |
 |---|---|---|---|---|---|
@@ -70,6 +70,7 @@ accepted-divergence entries (#96, #49, #50).
 | AD-47 | **Filed at Campaign V slice V11 (2026-07-29); the campaign's risk register scheduled this row here.** Multisample resolve sample POSITIONS are unspecified by both the Vulkan and D3D9 specifications, so acdream's MSAA-on silhouette edges do not match retail's pixel-for-pixel even at the same sample count. acdream's strict pixel gates therefore run with MSAA forced OFF on every arm, and MSAA-on gets only a relaxed visual smoke. | `src/AcDream.App/RuntimeOptions.cs` (`ACDREAM_MSAA_SAMPLES`); forced to 0 in `tools/run-offline-pixel-gate.ps1` | Measured, not assumed: plan §5.5.16 compared two backends at 4x and found **8.83% of the frame differing — 81,359 px of 921,600 — essentially all of it hugging foliage and silhouette edges**, which is ninety-fold over the 0.001 gate threshold. That is two implementations' sample patterns, not a renderer divergence, which is why forcing MSAA off is what makes the remaining difference attributable rather than a threshold relaxation. | Edge quality on thin geometry (fence rails, foliage, distant railings) differs from retail at the sub-pixel level whenever MSAA is on, which is the ordinary player configuration. Because the gates run MSAA off, **a real regression confined to the multisample path would not be caught by them** — that is the actual exposure this row records. | D3D9 `D3DRS_MULTISAMPLEANTIALIAS` / `D3DMULTISAMPLE_TYPE` as set by `RenderDeviceD3D::SetDefaultD3DStates @ 0x005a3800`; retail's sample pattern is the driver's, exactly as ours is |
 | AD-48 | **Filed at Campaign V slice V11 (2026-07-29).** Presentation is paced by the Vulkan swapchain present mode (FIFO, i.e. VSync) or by a refresh-rate software pacer when uncapped, rather than by retail's D3D9 `Present` with its own frame-rate limiter. Frame delivery cadence, and therefore input-to-photon latency, is a property of our present path rather than a port of retail's. | `src/AcDream.App/RuntimeOptions.cs:98-100`; `src/AcDream.App/Rendering/Gpu/Vk/VulkanSwapchain.cs` | Retail's limiter and ours both bound the frame rate to the display; the simulation is fixed-step and clock-driven, so gameplay timing does not ride on presentation cadence. The uncapped path exists for measurement and is not the shipping default. | A pacing mismatch shows up as judder or input latency that differs from retail's feel without any visual difference in a captured frame — invisible to every pixel gate by construction. Issue **#235** (the capped/RDP jump-presentation cadence alias) is the known live instance of this class. | D3D9 `IDirect3DDevice9::Present`; retail's frame limiter in `RenderDeviceD3D` |
 | AD-50 | **Filed at Campaign N slice N2 (2026-07-29).** The inbound sequence tracker's watermark (`highestIDReceived_`) initializes to **1**, not retail's zero-init of `ReceiverData`. Watermark INIT only — every mechanism (sanity window, duplicate/parked-key path, gap walk, re-park, RejectRetransmit abandonment) is the verbatim retail port. | `src/AcDream.Core.Net/Transport/InboundSequenceTracker.cs` (`AceInitialWatermark`) | ACE never emits S2C sequence 1: its `PacketSequence` starts unprimed at `uint.MaxValue`, the cleartext ConnectRequest takes NextValue 0, and the first ENCRYPTED flush re-primes CurrentValue to 1 so the first encrypted sequenced packet is 2 (ACE NetworkSession.cs:716-717 + Sequence/UIntSequence.cs:9-13,30-41; pinned by the N0 double and the N2 clean-lifecycle conformance test asserting min encrypted S2C sequence == 2 with zero NAKs). A zero-init watermark would gap-walk the permanent id-1 hole: one spurious NAK, the first pre-drawn word mis-assigned to id 1, and the keystream off by one from the very first encrypted packet. holtburger seeds the same value (crates/holtburger-session/src/session/api.rs:30, `last_server_seq: 1`), mirroring ACE's own C2S-side `lastReceivedPacketSequence = 1` (NetworkSession.cs:57). | Against a hypothetical server that DOES emit sequence 1 as its first encrypted packet (retail's own numbering), init-1 would classify it "not newer" and drop it as a duplicate — the mirror-image wedge. Only ACE-family servers exist for this client today. | `ReceiverData` zero-init (construction inside `SharedNet`; `highestIDReceived_` starts 0); `SharedNet::ProcessNewestSeqNum @ 0x00541930` (the walk that would mis-NAK id 1) |
+| AD-51 | **Filed at Campaign N slice N4 (2026-07-29).** The inbound sequence tracker keeps a reclaimed-word pool (per-parked-word draw ordinals + `PriorityQueue` consumed lowest-draw-order-first) that retail has no counterpart for: on a VALIDATED cleartext `RejectRetransmit`, the word the gap walk parked for the reject packet's OWN sequence is removed, every later-drawn parked word is shifted down one position, and the excess word feeds the next fresh draws. | `src/AcDream.Core.Net/Transport/InboundSequenceTracker.cs` (`OnCleartextRejectSequence`, `NextWord`, `ParkedWord`); trigger at `src/AcDream.Core.Net/WorldSession.cs` (RejectRetransmit consumption) | Retail's inbound invariant is "every missing id was an encrypted packet whose keystream word the server drew" — true against retail servers, whose cleartext packets always borrow live sequences (acks/NAKs reuse `highestIDSent_`; `FlowQueue::TransmitNewPackets @ 0x00547A60` sequences only reliable packets). ACE breaks it in exactly one place: `RejectRetransmit` takes a FRESH sequence through FlushPackets, cleartext, drawing NO S2C keystream word, and is cached (ACE NetworkSession.cs:299-304, :722-725, :743-748). Without the reclaim, our gap walk pre-draws a word for that id, the inbound stream runs permanently one word ahead, and every later encrypted packet fails checksum — the N2 desync class reintroduced through the reject path. The pool is provably empty against a retail server, so retail behavior is untouched. Reject BODY ids keep the N2 discard (their words were drawn on both sides — consumed-in-place). Known unreachable corner: a reject whose own id later appears inside another reject's body (first reject pruned after 120 s of sustained loss with the session alive) would discard a never-drawn word; probabilistically impossible against ACE's 60 s silence timeout and the 0.6 s NAK cadence. | Against a hypothetical non-ACE server that assigns fresh cleartext sequences to packets OTHER than RejectRetransmit, those ids would still mis-park with no reclaim trigger — inbound desync. Only ACE-family servers exist for this client today, and ACE has exactly the one path. | `SharedNet::ProcessNewestSeqNum @ 0x00541930` (the gap walk whose invariant ACE breaks); `SharedNet::HandleEmptyAck @ 0x005448F0` (retail's reject consumption — body ids only, no own-sequence machinery because retail never needs it) |
 | AD-38 | Outgoing teleport viewports retire when retail's quantized animation level exceeds the last captured visible level 1022 (index 96), suppressing levels 1023/1024 up to 20.2 ms before retail's literal `elapsed >= 1.0` state edge. Incoming fades retain the exact timer. | `src/AcDream.Core/World/TeleportAnimSequencer.cs` (`OutgoingViewportReachedTerminalProjection`) | An uncapped 2000 FPS pass can publish the finite tunnel at levels 1023/1024 even though the paired 2013 retail capture switches viewports after 1022. The table-level cutover preserves the captured visible viewport ordering without throttling the application. | Exit sound, viewport replacement, and logout tunnel entry can occur at most two easing-table quanta (about 20.2 ms) earlier than retail's logical timer. | `UIGlobals::GetAnimLevel @ 0x004EE540`; `gmSmartBoxUI::UseTime @ 0x004D6E30`; paired retail/acdream captures documented in `docs/research/2026-07-15-retail-portal-space-pseudocode.md` |
 | AD-1 | Lost-cell machinery replaced by recoverable outdoor demote (**#107** safety net) + outdoor-restore `max(terrainZ, z)` under-terrain lift; retail goes `GotoLostCell` | `src/AcDream.Core/Physics/PhysicsEngine.cs:553` (+ :808) | acdream has no lost-cell state machine; outdoor landcell is the recoverable equivalent; the #107 auto-entry hold should make the demote branch unreachable | Gap in the hold → player committed to outdoor terrain inside/under a building (fake-grounded spawn, fall-through); a legit below-heightmap server restore is silently lifted — upward warp vs server | `GotoLostCell` pc:283418; `SetPositionInternal` 0x00515bd0, pc:283892-283945 |
 | AD-2 | Async readiness gates replace retail's synchronous destination cell load. **#229 refinement (2026-07-20):** login and F751 portal-space exit now share `WorldRevealReadinessBarrier`, so neither path can expose the normal viewport until the same render-publication, composite-texture, and collision domains converge. A hydratable indoor claim requires its owning Near-tier static/EnvCell mesh set, destination composites, and exact EnvCell physics (`IsSpawnCellReady`); an outdoor claim requires those render domains plus terrain/collision residency for the required Near ring. Hard-recenter generations and tier-aware completion application prevent stale overlapping loads/unloads or Far/Near jobs from opening or erasing the gate; mesh upload remains separate from balanced landblock ownership. Claims beyond NumCells still take the loud unhydratable-placement path. `RuntimeWorldTransitState` owns the shared reveal generation, accepted readiness, transit correlation, and exact generation/cell-scoped host-acknowledgement suffix. `WorldRevealCoordinator` is a graphical adapter holding only App resource receipts; normalized Runtime checkpoints observe ownership without defining another readiness path. **Slice E3 refinement (2026-07-24):** the same generation now publishes an immediate `WorldGenerationQuiescence` edge: old-world drawing/spatial queries, simulation/effect clocks, reconciliation, targeting, and 3-D audio stop while retained physical teardown advances through metered cursors and destination network/UI/streaming/readiness remain live. **Slice E4 refinement (2026-07-24):** accepted render/physics/static publication may span update frames through retained exact cursors, but reveal still consumes only the completed spatial/render-ready generation; building and EnvCell snapshots remain invisible until complete and the final spatial identity swap stays observer-atomic. **Slice E5 refinement (2026-07-24):** the reveal generation owns one exact destination reservation across every typed budget dimension. Stale completion cannot consume or clear its replacement, and hydratable incomplete content is never force-revealed; portal transit retains the DAT tunnel and centered retail wait cue until readiness converges. The hold→materialize→regain-control lifecycle remains owned by `TeleportAnimSequencer`. | `src/AcDream.Runtime/World/RuntimeWorldTransitState.cs`; `src/AcDream.App/Streaming/WorldRevealCoordinator.cs`; `src/AcDream.App/Streaming/WorldGenerationQuiescence.cs`; `src/AcDream.App/Streaming/WorldRevealReadinessBarrier.cs`; `src/AcDream.App/Streaming/StreamingOriginRecenterCoordinator.cs`; `src/AcDream.App/Streaming/LandblockPresentationPipeline.cs`; `src/AcDream.App/Streaming/StreamingController.cs`; `src/AcDream.App/Rendering/PortalTunnelPresentation.cs`; `src/AcDream.App/UI/PortalWaitNoticeController.cs`; `src/AcDream.App/Streaming/GpuWorldState.cs` (`IsRenderReady`); `src/AcDream.App/Rendering/Wb/LandblockSpawnAdapter.cs`; `src/AcDream.Core/Physics/PhysicsEngine.cs` (`IsSpawnCellReady`, `IsNeighborhoodTerrainResident`) | This is the asynchronous equivalent of retail leaving `SmartBox::position_update_complete` false while `CellManager::blocking_for_cells` is set: neither initial login nor portal arrival may reveal or continue simulating an old/partial collision world, a terrain-only Far shell, or a published-but-not-drawable GPU landblock. Indoor does not require a terrain heightmap, only the owning render landblock and exact EnvCell. | Gate opens early → grey/untextured first login or portal reveal, free-fall, wrong-cell rooting, missing scenery, or a still-active old generation; predicate never satisfies (streamer/DAT/upload failure) → login remains behind the world render gate, while portal transit remains in the authored tunnel and presents the centered wait cue after five seconds. | `SmartBox::UseTime` 0x00455410; `gmSmartBoxUI::UseTime` 0x004D6E30; `gmSmartBoxUI::EndTeleportAnimation` 0x004D65A0 |

docs/plans/2026-07-29-network-transport-campaign.md

@@ -254,7 +254,7 @@ verbatim in each implementer prompt.
 | N0 | complete | `7e9134b4` + `e3958610` | ACE-behaviour double + virtual clock + lossy link; the review fix-up added the `Session.CheckState` inbound gate, faithful `SendBundle` coalescing/splitting, two-phase termination, an ACE-loose C2S fragment parse, and ACE's MessageBuffer edge cases. 687 Core.Net tests green. N1 folded in the re-review's `ProcessFragment` two-branch split (existing-buffer checks Complete; new-buffer parks without checking — the zero-count buffer stays parked). |
 | N1 | complete | `43e60a69` | Outbound sent-packet cache + resend on NAK (`Transport/`: `TransportClock`, `SequenceMath`, `SentPacketStore`, `OutboundFlowQueue`, `ReliableTransport`, `TransportStats`); `PacketCodec.FinalizeInPlace` sealed-checksum overload; `WorldSession` sweep in Tick + both handshake pump loops; TS-57 filed, TS-27 narrowed to inbound-only. **Fable review PASS.** Advisories: fresh sends keep `Time=0` (byte-identical wire; retail stamps the interval on every packet and ACE ignores the field — N3 folds the retail stamp in with the cadence work); the stale-NAK single-redundant-resend window is shared with retail (pending prunes at flush, after transmit — same frame order as `RecipientData::UseTime`). |
 | N2 | complete | `46d209d0` — **Fable review PASS** (tracker/codec-split/admission verified pre-commit against retail rules; gates lifecycle+nine-stop both PASS) | Inbound sequence-aligned ISAAC + NAK set (`Transport/InboundSequenceTracker`: watermark, sanity window, duplicate/parked-key path, sequence-ordered gap-walk pre-draw, verify-failure re-park, RejectRetransmit abandonment — `ProcessNewSeqNum @ 0x00544690`, `ProcessNewestSeqNum @ 0x00541930`, `SeqIDSanityCheck @ 0x00543A20`, `AddNakked @ 0x00549240`, `HandleEmptyAck @ 0x005448F0`); `PacketCodec` split into keystream-free `TryParseBorrowed` + `VerifyChecksum` (`TryDecodeBorrowed` deleted); `RejectRetransmit` ids exposed on both optional-header decoders; `ReliableTransport` now owns both keystreams; stats gained `InboundDupsDropped`/`InboundSanityDrops`/`ChecksumFailures`/`KeysParked`. Watermark init 1 is the AD-50 ACE adaptation (retail zero-init vs ACE's re-prime dance — first encrypted S2C is sequence 2; holtburger api.rs:30 agrees); pinned by the clean-lifecycle conformance test (zero NAKs, min encrypted S2C sequence == 2). 716 Core.Net tests green. **N3/N4 handoff note:** the interim per-packet reflex ack acks the ARRIVING sequence even while a gap is parked, so ACE prunes the lost id from its S2C cache (`AcknowledgeSequence` strictly-below) before N4 can NAK it — message-level recovery of a real loss needs N3's retail NAK-xor-ack sweep (§2.3's mutual exclusivity is load-bearing). Also noted for N4: ACE's `RejectRetransmit` consumes a fresh CLEARTEXT sequence via FlushPackets (no keystream word), so the client's gap walk parks a word for an id that never had one server-side — a real retail-vs-ACE incompatibility to resolve in N4's design (retail never assigns new sequences to cleartext). |
-| N3 | complete | `0265cc42` — Opus review PASS (advisories folded into N4: transitional-state wording, SharedInit citation, pump-order wording, control-packet Time/Iteration rule, stale budget-break comment) | AckNakScheduler + 2.0 s cumulative ack (`Transport/AckNakScheduler`): ONE shared timestamp (`ReceiverData::timeStamp_` @ +0x10) arbitrating NAK-xor-ack per sweep (`ClientNet::ProcessConnection @ 0x00545450`); the ack is one cleartext exact-flags `AckSequence` carrying the tracker's `highestIDReceived_` behind the >= 2.0 s gate (`SharedNet::EnqueuePak @ 0x00543B10` — the binary's only 0x4000 construction site), armed at connection birth (`ReceiverData::Init @ 0x00548EF0`). The Phase 4.9 per-packet reflex ack and `WorldSession.SendAck` are DELETED; the `[net-tick]` acks/s probe now reads `Stats.AcksSent`. Sweep order per `FlowQueue::Empty @ 0x00548A20`: interval clock, NAK/ack arbitration, pending resends, prune. **N3 transitional state:** a non-empty NAK set suppresses the ack and emits NOTHING (no NAK yet) — safe for exactly one slice on loopback; N4 completes the branch. **N1 advisory retired (fold-in):** fresh reliable sends now stamp `Header.Time` = the current interval id (`FlowQueue::TransmitNewPackets @ 0x00547A60`, header build at 0x00547A84); ACE ignores inbound `Header.Time`, so the wire is unaffected. New `WorldSession.TransportClockSource` seam drives the gate on virtual time. 723 Core.Net tests green (keepalive property proven: a quiet session's 2 s acks refresh ACE's 60 s deadline across a 120 s virtual horizon; storm collapse: a 50-packet flood → ONE ack; the model accepts the reused-sequence ack without advancing its watermark). Connected lifecycle + canonical nine-stop gates PASS. |
-| N4 | pending | — | |
+| N3 | complete | `0265cc42` — Opus review PASS (advisories folded into N4: transitional-state wording, SharedInit citation, pump-order wording, control-packet Time/Iteration rule, stale budget-break comment) | AckNakScheduler + 2.0 s cumulative ack (`Transport/AckNakScheduler`): ONE shared timestamp (`ReceiverData::timeStamp_` @ +0x10) arbitrating NAK-xor-ack per sweep (`ClientNet::ProcessConnection @ 0x00545450`); the ack is one cleartext exact-flags `AckSequence` carrying the tracker's `highestIDReceived_` behind the >= 2.0 s gate (`SharedNet::EnqueuePak @ 0x00543B10` — the binary's only 0x4000 construction site), armed at connection birth (`ReceiverData::Init @ 0x00548EF0`). The Phase 4.9 per-packet reflex ack and `WorldSession.SendAck` are DELETED; the `[net-tick]` acks/s probe now reads `Stats.AcksSent`. Sweep order per `FlowQueue::Empty @ 0x00548A20`: interval clock, NAK/ack arbitration, pending resends, prune. **N3 transitional state (closed by N4):** a non-empty NAK set suppressed the ack and emitted NOTHING — the exposure was real even on loopback, just low-probability: one receive-buffer drop parks an id, every later sweep takes the silent NAK branch, acks stop (witness: `[net-tick] acks/s=0`), and ACE disconnects the quiet session at its 60 s timeout. N4 completed the branch. **N1 advisory retired (fold-in):** fresh reliable sends now stamp `Header.Time` = the current interval id (`FlowQueue::TransmitNewPackets @ 0x00547A60`, header build at 0x00547A84); ACE ignores inbound `Header.Time`, so the wire is unaffected. New `WorldSession.TransportClockSource` seam drives the gate on virtual time. 723 Core.Net tests green (keepalive property proven: a quiet session's 2 s acks refresh ACE's 60 s deadline across a 120 s virtual horizon; storm collapse: a 50-packet flood → ONE ack; the model accepts the reused-sequence ack without advancing its watermark). Connected lifecycle + canonical nine-stop gates PASS. |
+| N4 | complete | SHA recorded at N5 kickoff | Client NAK emission + RejectRetransmit consumption. `AckNakScheduler` completes the NAK branch: one cleartext exact-flags `RequestRetransmit` per sweep behind the STRICT 0.6 s gate on the ONE shared timestamp (`SharedNet::EnqueueNaks @ 0x00543BD0` — the 0x41-mask x87 test at 0x00543C03 proceeds only on strictly-greater, contrast the ack's >=), body u32 count + ids ascending capped at 114 (`ReceiverData::GetNaks @ 0x005490C0`, cap 0x72), borrowed sequence, never an ack in a NAK sweep. Control-header rule decided for BOTH emissions: `Time` = interval id, `Iteration` = session iteration, per the shared retail header build (`FlowQueue::TransmitNewPackets @ 0x00547A60` @ 0x00547A84); ACE reads neither. THE design piece: the AD-51 reclaimed-word pool in `InboundSequenceTracker` closes the ACE cleartext-reject keystream hazard the N2 ledger row recorded — ACE's `RejectRetransmit` consumes a fresh cleartext sequence with NO keystream word, so the gap walk mis-parks a word for it and the whole inbound stream runs one word ahead. On a VALIDATED cleartext reject (`WorldSession` calls `OnCleartextRejectSequence` post-checksum), the tracker removes the mis-park, bubble-shifts every later-drawn parked word down one position (per-word draw ordinals; ascending id ⇔ ascending draw order), and pools the excess for the next fresh draws, consumed lowest-draw-order-first — exact for any number of interleaved rejects in any arrival order (a plain FIFO is NOT: reject-after-higher-arrival crosses the parked chain, and dual out-of-order rejects pool out of draw order — both pinned by tests). Reject BODY ids keep N2's discard (word-bearing server-side, consumed-in-place). N3 advisories all folded: honest transitional wording (above), `ReceiverData::SharedInit @ 0x00548EF0` (from `Init @ 0x00548FA0`) citation, `FlowQueue::Empty` pump-order comment (TransmitNaks → TransmitAcks → TransmitNewPackets, interval increment LAST @ 0x00548A9D; our clock-first order is cosmetic vs ACE), the Time/Iteration rule, and the stale `WorldSession` budget-break comment. Gate arithmetic hardened: gate ticks now round (0.6 has no exact double; truncation opened the strict gate AT the boundary). 737 Core.Net tests green, including: strict-gate boundary, shared-timestamp both directions, NAK-suppresses-ack, full wire-shape + 114-cap pins, model-served retransmission round trip, five tracker reclaim proofs, the 130-s virtual prune → fresh-sequence reject system test (victim abandoned, later traffic decodes, pool drains to zero), 10 s long-loss (NAKs on the gate cadence, zero acks, heal inside the window), and the capstone soak: 2% seeded bidirectional loss × 10,000 messages → zero message loss both ways, ACE crypto headroom 256 at convergence with a ≥250 no-erosion floor mid-flight, NAK set / reclaim pool / pending resends / ACE out-of-order buffer all zero, cache at the single watermark entry (retail Flush prunes STRICTLY below the ack). Soak notes: ACE never NAKs a quiet client (§3 row 1), so convergence keeps a C2S trickle flowing — a real idle-client tail loss heals only on the next action, an ACE constraint outside N4's scope. |
 | N5 | pending | — | |
 | N6 | pending | — | |