feat(net): N1 - outbound sent-packet cache + resend on NAK

Campaign N Slice N1 (docs/plans/2026-07-29-network-transport-campaign.md
S2.1) - the direct #260 fix: every sent reliable packet is now cached and
re-emitted, header-rebuilt, when ACE NAKs a client-sequence gap. One lost
C2S datagram no longer voids every subsequent action for the session's
lifetime.

New src/AcDream.Core.Net/Transport/:
- TransportClock: injectable monotonic source + retail's 0.5 s interval
  counter (ClientFlowQueue::IncrementLocalInterval @ 0x00547F10, tail
  `intervalID_ += elapsed`; the same function's ~3 s TimeSync/Echo cadence
  stays deferred per TS-58).
- SequenceMath: wrap-safe IsNewer/Max (TimeStampUtils::lhs_newer
  @ 0x00543890, reduced to the signed-difference form).
- SentPacketStore: FIFO of ArrayPool-rented wire buffers; Add asserts
  optionalLength == 0 (NetPacket::RemoveDisposableOptionalHeaders
  @ 0x00549510 pinned as a no-op under standalone-control); FlushOlderThan
  pops strictly-older wrap-safe (SentPacketStore::AddSentPacket
  @ 0x0054AB00, Flush @ 0x0054ACD0).
- OutboundFlowQueue: owns the outbound ISAAC, highestIDSent (starts 1,
  pre-increment, wrap 0xFFFFFFFF->1, never 0), the fragment sequence, the
  store, the wrap-safe sorted dedup pending-resend list
  (FlowQueue::EnqueueAcks @ 0x005488E0), and the flushNum_ ack watermark.
  Cache commit happens AFTER a successful send
  (FlowQueue::TransmitNewPackets @ 0x00547A60, commit site 0x00547C85).
  NAK ids[0] folds into the watermark as retail's implicit cumulative ack
  (RecipientData::ProcessNaks @ 0x00547010). A resend rebuilds ONLY the
  20-byte header: flags Retransmission|EncryptedChecksum (|BlobFragments
  with fragments), Time = current interval id, Sequence/Id/Iteration/
  DataSize verbatim, checksum = fresh header hash + stored sealed checksum
  (FlowQueue::TransmitAcks @ 0x005485B0, DequeueAck @ 0x005472F0). The
  original ISAAC key rides inside the sealed value - no new keystream word
  is ever drawn (CryptoSystem::EncryptData @ 0x0065FF40 non-null-key
  path; landmines #1/#2). Resend only on explicit NAK (landmine #3).
- ReliableTransport: composition + Sweep() (interval clock, resends,
  prune). The AckNakScheduler joins in N3/N4; ack behavior is untouched
  this slice.
- TransportStats: unconditional counters (ResendsSent,
  NakRequestsReceived, UncachedNakIds, AcksConsumed) + CacheDepth.

PacketCodec.FinalizeInPlace gains an overload returning (isaacKeyUsed,
sealedChecksum) where sealedChecksum is the pre-header-hash value -
payloadHash cleartext, isaacKey ^ payloadHash encrypted (retail
NetPacket::checksum_). The old signature forwards; encode bytes are
unchanged. Decode is untouched.

WorldSession integration is minimal: the transport is constructed at
ISAAC-seeding time (first reliable packet keeps sequence 2 / fragment 1,
byte-identical to pre-N1); SendGameMessage delegates (probe fseq/pseq now
read the transport); SendAck's borrowed sequence reads HighestIdSent
(identical value, behavior EXACTLY as-is this slice); ProcessDatagram
consumes RequestRetransmit + AckSequence BEFORE the unchanged reflex ack;
the sweep runs at the end of Tick() after the budget break AND inside
both blocking handshake pump loops (Connect step 4, EnterWorld
ServerReady - landmine #8), gated on _transportNegotiated; Dispose
returns the rented cache buffers.

Bookkeeping: TS-57 filed in the divergence register (uncached NAK ids
dropped silently + counted instead of retail's RejectRetransmit - ACE
no-ops the reject and the standalone unsequenced form would trip ACE's
watermark hole); TS-27 narrowed to the inbound direction in the same
commit; the stale WorldSession class-doc gap list corrected.

N0 fold-ins from the re-review: AceSessionModel.ProcessFragment split
into ACE's two literal branches (existing-buffer checks Complete,
NetworkSession.cs:495-507; new-buffer constructs + adds + TryAdds WITHOUT
checking Complete, :509-518), and the zero-count-fragment test now pins
the parked dead buffer (PartialFragmentBufferCount 0 -> 1). e3958610
recorded in the campaign ledger's N0 row.

Tests: 15 new in Transport/OutboundReliableTransportTests.cs - store
FIFO/strict/wrap-safe flush with rent/return balance via a counting
pool, interval-clock start/advance/wrap, resend header shape (flags
exactly 3 or 7, Time = interval, verbatim fields, checksum identity,
bit-identical body), resend-consumes-no-ISAAC-word, uncached-NAK
counting, ids[0] watermark fold + strict prune, wrap-safe ack max,
conformance resend verifying under AceCryptoModel with the ORIGINAL
parked key (Headroom 256, zero orphans, ordering restored), an
end-to-end FakeAceTransport lossy run (10 game actions, C2S #5 dropped,
all 10 dispatched in order, exactly one resend, session alive), and
zero-alloc steady-state SendGameMessage.

Gates: dotnet build green; AcDream.Core.Net.Tests 702/702; full-solution
Release 9,723 passed / 5 skipped / 0 failed; connected world-lifecycle
gate vs local ACE RESULT=PASS (0 failures, both sessions exit 0; one
pre-existing expected world-edge landblock-miss warning).

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

docs/architecture/retail-divergence-register.md

@@ -226,7 +226,7 @@ AP-94..AP-112 for the confirmed retail-UI completion gaps.
 | AP-123 | Item cooldowns use the retained toolkit's existing procedural `UiItemSlot` leaf rather than materializing retail's ten `m_elem_Icon_Cooldown_*` child elements. The group lookup, remaining-time formula, exact DAT sprites, step choice, and topmost ReadOrder-8 outcome are faithful. | `src/AcDream.App/UI/Layout/ItemCooldownUiController.cs`; `src/AcDream.App/UI/UiItemSlot.cs` | `UiItemSlot` already consumes/reproduces UIItem children procedurally under the IA-15 retained-toolkit architecture. Selecting one imported sprite at draw time gives every inventory/equipment/shortcut alias the same output without a parallel widget tree or per-cell timers. | A future feature that observes the individual cooldown child visibility/state rather than the rendered UIItem could see no child elements even though the cell looks and advances correctly. | `CEnchantmentRegistry::OnCooldown @ 0x005943C0`; `UIElement_UIItem::UpdateCooldownDisplay @ 0x004E1E20`; common UIItem prototype `0x1000033E` |
 | AP-124 | Local ACE omits the new object's CreateObject to the initiating session after `StackableSplitTo3D`, sending only F748 Position for the previously unknown GUID. acdream retains retail's one pending split source/count/time identity for ten seconds and, only for that otherwise-impossible unknown Position, hydrates a canonical clone of the source description with the new GUID and authoritative world placement. | `src/AcDream.App/World/InventoryWorldDropProjectionController.cs`; `src/AcDream.App/UI/ItemInteractionController.cs`; `src/AcDream.App/Physics/LiveEntityNetworkUpdateController.cs` | Nearby/reconnecting clients receive the ordinary CreateObject, while the initiator otherwise cannot render the authoritative object until relog. A server that sends CreateObject never enters this path; the pending identity is consumed before normal hydration and all other unknown Positions remain rejected. | ACE's F748 does not carry WCID or stack size, so an unrelated unknown Position arriving during the exact pending ten-second window could be associated with the split. Retail confirms WCID/count from CreateObject; removing the approximation requires ACE to send that packet to the initiator. | `ACCWeenieObject::UIAttemptSplitTo3D @ 0x0058D850`; `ACCWeenieObject::DeclareValid @ 0x0058E340`; ACE `Player.HandleActionStackableSplitTo3D` / `TryDropItem`; `docs/research/2026-07-26-retail-inventory-placement-and-world-drop-pseudocode.md` |
 
-## 4. Temporary stopgap (TS) — 38 active rows + TS-37 historical note (TS-20 retired 2026-07-16 — the later named-retail audit disproved the proposed DrawingBSP polygon filter; TS-37 is a retired-row historical note, not an active count; TS-39 retired R5-V3 — sticky seams bound to the ported PositionManager/StickyManager, radii threaded; TS-45 retired 2026-07-07 — hand-rolled `SphereCollision` replaced by the faithful CSphere family port, fixing the player-vs-monster crowd wedge; TS-3 retired 2026-07-07 — `frames_stationary_fall` accounting ported in the #182 verbatim UpdateObjectInternal rebuild, fixing the airborne falling-animation wedge; TS-41 retired 2026-07-07 — SERVERVEL synth-velocity remote body-drive replaced by the retail interp catch-up + unconditional MovementManager::UseTime, the remote-creature de-overlap #184; TS-42 retired 2026-07-19 — semantic animation completion now precedes the ordered Target/Movement/PartArray/Position tail; TS-44 narrowed again 2026-07-19 — complete orientation joined interpolation, only during-stick enqueue suppression remains)
+## 4. Temporary stopgap (TS) — 39 active rows (TS-57 filed 2026-07-29 at Campaign N slice N1 — no outbound RejectRetransmit; TS-27 narrowed same slice to the inbound direction) + TS-37 historical note (TS-20 retired 2026-07-16 — the later named-retail audit disproved the proposed DrawingBSP polygon filter; TS-37 is a retired-row historical note, not an active count; TS-39 retired R5-V3 — sticky seams bound to the ported PositionManager/StickyManager, radii threaded; TS-45 retired 2026-07-07 — hand-rolled `SphereCollision` replaced by the faithful CSphere family port, fixing the player-vs-monster crowd wedge; TS-3 retired 2026-07-07 — `frames_stationary_fall` accounting ported in the #182 verbatim UpdateObjectInternal rebuild, fixing the airborne falling-animation wedge; TS-41 retired 2026-07-07 — SERVERVEL synth-velocity remote body-drive replaced by the retail interp catch-up + unconditional MovementManager::UseTime, the remote-creature de-overlap #184; TS-42 retired 2026-07-19 — semantic animation completion now precedes the ordered Target/Movement/PartArray/Position tail; TS-44 narrowed again 2026-07-19 — complete orientation joined interpolation, only during-stick enqueue suppression remains)
 
 | # | Divergence | Where (file:line) | Why it is safe / justified | Risk if assumption breaks | Retail oracle |
 |---|---|---|---|---|---|
@@ -247,7 +247,7 @@ AP-94..AP-112 for the confirmed retail-UI completion gaps.
 | TS-23 | PK/PKLite/Impenetrable mover bits never set (PlayerKillerStatus not parsed from PD); moverFlags always `IsPlayer ∣ EdgeSlide` — for BOTH the LOCAL player mover and, as of **#184 Slice 2b**, every remote-PLAYER dead-reckoning mover | `src/AcDream.Runtime/Gameplay/PlayerMovementController.cs:1177`; `src/AcDream.App/Physics/RemotePhysicsUpdater.cs` (`Tick` sweep, `IsPlayerGuid` branch) | Non-PK pair walks through other non-PK players — retail's default for ACE's character-creation defaults. Slice 2b gave the remote-player mover `IsPlayer` (was bare `EdgeSlide`) so remote-vs-remote non-PK players WALK THROUGH exactly like the local player and like retail (they still collide with monsters + terrain + walls); without it Slice 2b would have de-overlapped players (MORE solid than retail) | On a PK/PKLite character the client lets players walk through where retail collides — now for the local player AND remote-vs-remote — the moment PvP statuses enter play (M2+) | PWD._bitfield acclient.h:6431-6463; pc:406898-406918; FindObjCollisions PvP block pc:276812 (mover IsPlayer via OBJECTINFO::init 0x0050cf30 `state\|=0x100`) |
 | TS-24 | RawMotionState action list always empty at runtime — the packer emits `num_actions` (bits 11–15) + per-action u16 pairs (L.2b, `RawMotionState::Pack` 0x0051ed10), and R3-W1 gives `RawMotionState`/`InterpretedMotionState` the retail-faithful action FIFO (`AddAction`/`RemoveAction`/`ApplyMotion`/`RemoveMotion`, `src/AcDream.Core/Physics/RawMotionState.cs` + `MotionInterpreter.cs`), but nothing calls `AddAction` yet — the outbound caller still builds an empty `Actions` list, so discrete motion events (emotes, one-shots) are still never broadcast | `src/AcDream.App/Rendering/GameWindow.cs:8297` (empty Actions); packer `src/AcDream.Core.Net/Messages/RawMotionStatePacker.cs:91`; FIFO capability `src/AcDream.Core/Physics/RawMotionState.cs` | Discrete client-initiated motions (D2) not wired yet; packer-ready, state-ready (W1), runtime emission lands with R3-W2's `add_to_queue`/`DoInterpretedMotion` population | When player-triggered emotes land, they silently never broadcast — observers see idle while the local client animates | `RawMotionState::Pack` 0x0051ed10; num_actions `PackBitfield` acclient.h:46487 |
 | TS-25 | `current_style` (stance, flag bit 0x2) never populated at runtime — the packer now emits it when it differs from the retail default 0x8000003D (L.2b), but the outbound caller leaves `CurrentStyle` at default (stance not tracked here) | `src/AcDream.App/Rendering/GameWindow.cs:8286` (CurrentStyle left default); packer `src/AcDream.Core.Net/Messages/RawMotionStatePacker.cs:80` | Stance switching is M2 combat scope | Once combat-mode switching ships, mid-stance MoveToStates omit the style — server/observers keep the stale stance, wrong cycle family for every subsequent movement | `RawMotionState::Pack` current_style 0x0051ed10 |
-| TS-27 | Retransmit handling absent: `RetransmitRequests`/`RejectRetransmit` parsed, but nothing re-sends lost outbound or requests missing inbound sequences (class-doc gap list otherwise stale — ack/position/chat exist) | `src/AcDream.Core.Net/WorldSession.cs:29` | Deferred since the one-shot test harness; dev loop is loopback (no loss) | On any lossy link a dropped fragment is gone forever — entities never spawn, chat vanishes, reassembly stalls; server retransmit requests ignored until session timeout. Stale doc list also misleads readers | PacketHeaderFlags RequestRetransmit 0x1000 / Retransmission 0x1 |
+| TS-27 | **NARROWED 2026-07-29 (Campaign N Slice N1)** — OUTBOUND is ported: sent-packet cache + header-rebuilt resend on server `RequestRetransmit`, `ids[0]` implicit ack, wrap-safe watermark prune (`src/AcDream.Core.Net/Transport/`). Residual: INBOUND loss is still fatal — no sequence-aligned inbound ISAAC discipline, no client NAK emission, no `RejectRetransmit` consumption (Campaign N slices N2/N4) | `src/AcDream.Core.Net/WorldSession.cs` (`ProcessDatagram` inbound path); `docs/plans/2026-07-29-network-transport-campaign.md` §2.2/§2.3 | Campaign N executes the port one direction per slice; the N0 ACE double grades each slice before the next lands | One lost S2C packet still shifts the inbound keystream permanently — every later encrypted packet fails checksum and the session goes silently deaf until timeout | `SharedNet::ProcessPacket @ 0x00544790`; `ReceiverData::AddNakked @ 0x00549240`; `SharedNet::EnqueueNaks @ 0x00543BD0` |
 | TS-28 | **NARROWED 2026-07-15** — F751 teleports now resend LoginComplete only after the DAT-authored portal-space viewport and final world fade finish. Initial login still sends LoginComplete directly from the PlayerCreate (0xF746) handler and does not enter the portal-space presentation. | `src/AcDream.Core.Net/WorldSession.cs` (PlayerCreate branch); `src/AcDream.App/Rendering/GameWindow.cs` (F751 `FireLoginComplete`) | The live-session bootstrap currently needs the acknowledgement to unlock the initial authoritative object/property stream; moving initial login behind the App presentation requires an explicit session→presentation readiness contract rather than withholding it inside Core.Net | Initial login can expose server updates earlier than retail and skips the wormhole presentation; recalls/portals now have retail ordering | `gmSmartBoxUI::UseTime @ 0x004D6E30`; retail post-EnterWorld flow; holtburger `client/messages.rs:391-422` |
 | TS-29 | Background music (MIDI) + ambient loops not ported: PlayMusic/StopMusic no-op; StartAmbient reserves a handle that never plays | `src/AcDream.App/Audio/OpenAlAudioEngine.cs:331` | Explicitly outside R5 audio-phase scope; a landblock-attached ambient system is planned separately | Silent world where retail has music/atmosphere; code trusting StartAmbient's handle to mean "playing" is already subtly wrong (StopAmbient looks up a never-created source) | retail MIDI + ambient system (r05) |
 | TS-30 | Chat DAT elements `0x10000522`–`0x10000525` render but have no controller semantics; the older claim that they are numbered in-window filter tabs is **unproven** | `src/AcDream.App/UI/Layout/ChatWindowController.cs` | Named retail proves separately filtered main/floaty chat windows, not an in-window numbered-tab model. Wave 5 must live/DAT-confirm these element roles before assigning behavior | The controls may be inert today, but inventing tab switching could be a larger divergence than leaving an unconfirmed role inactive | `gmMainChatUI @ 0x004CCCC0..0x004CE2A0`; correction in `docs/research/2026-07-10-retail-panel-behavior-pseudocode.md` |
@@ -271,6 +271,7 @@ AP-94..AP-112 for the confirmed retail-UI completion gaps.
 | TS-53 | acdream advances retained UI time on the draw seam and local teleport/UI-camera presentation after its SmartBox-shaped object → inbound network → CommandInterpreter barrier. Retail `Client::UseTime` calls `UIElementManager::UseTime` first, whose global time message reaches `gmSmartBoxUI::UseTime`, and publishes player-camera work from the physics/player callback rather than one post-network camera tail. Slices 6–7 preserve the accepted host order as ownership-only extractions. | `src/AcDream.App/Update/UpdateFrameOrchestrator.cs` (post-live-frame teleport/camera phases); `src/AcDream.App/Rendering/PrivatePresentationRenderer.cs` (`RetainedGameplayUiFrame.Render`); `docs/plans/2026-07-21-gamewindow-slice-6-update-frame-orchestration.md`; `docs/plans/2026-07-22-gamewindow-slice-7-render-frame-orchestration.md` | Current retained UI, portal transit, reveal, camera, and connected movement traces are accepted; changing cross-subsystem host order while extracting ownership would combine a behavior change with the structural cutover. | Retained UI, teleport, and camera presentation can observe same-frame object/inbound/player state one host update earlier or later than retail at transition boundaries; a future exact host-order port must prove UI, input, reveal, and camera consequences together. | `Client::UseTime @ 0x00411C40`; `UIElementManager::UseTime`; `gmSmartBoxUI::UseTime @ 0x004D6E30`; `CPhysics::UseTime @ 0x00509950`; retire only with a focused host-order port and connected portal/camera comparison |
 | TS-54 | AdminEnvirons sound values `0x65..0x7B` are diagnosed by retail enum name but do not play audio. Retail checks that the local player physics object and UI sound table exist, then calls `SoundManager::PlaySoundFromCenter(Sound_UI_*, table)` for Roar through Thunder6. | `src/AcDream.App/World/WorldEnvironmentController.cs` (`ApplyAdminEnvirons`) | The current audio owner has no typed retail UI-sound-table binding; logging preserves the inbound evidence without inventing wave DIDs or routing the sounds through positional world audio. | Server-authored ambience/thunder packets are silent in acdream while retail plays the centered UI sound. | `CPlayerSystem::Handle_Admin__Environs @ 0x0055DE20` (`0x0055E07F..0x0055E2C7`); `SoundManager::PlaySoundFromCenter @ 0x00550950` |
 | TS-55 | AdminEnvirons fog values remain a color-only `WeatherSystem.Override` approximation. Retail values 1..5 install authored ambient color/level plus fog color/max; value 6 also forces transition/min/max and blanks radar; Clear restores all override fields and radar; `0x270F` installs a separate authored override. | `src/AcDream.App/World/WorldEnvironmentController.cs` (`ApplyAdminEnvirons`); `src/AcDream.Core/World/WeatherState.cs` (`EnvironOverrideColor`) | Preserves the already accepted enum bridge while Slice 8 moves ownership; porting the complete environment/radar presentation is a separate behavior change requiring focused visual gates. | Forced-fog hue, density, scene ambient, and radar blanking differ from retail; `0x270F` is ignored. | `CPlayerSystem::Handle_Admin__Environs @ 0x0055DE20` (`0x0055DE2B..0x0055E344`) |
+| TS-57 | No outbound `RejectRetransmit`: a server NAK for an id no longer in the sent-packet cache is dropped silently (counted in `TransportStats.UncachedNakIds`); retail answers `RejectRetransmit @ FlowQueue` so the server abandons the id immediately | `src/AcDream.Core.Net/Transport/OutboundFlowQueue.cs` (`OnRetransmitRequest`) | ACE parses `RejectRetransmit` and no-ops it (NetworkSession.cs — no handler), and the standalone unsequenced form would trip ACE's watermark hole (campaign doc §3 row 3: any cleartext non-ack packet with a live sequence advances the watermark and skips a real packet forever) | Against a server that DOES honor RejectRetransmit, an uncached NAKed id keeps being re-requested until that server's own NAK give-up logic fires — never against ACE, which forgets the id when its next cumulative ack passes it | `RecipientData::ProcessNaks @ 0x00547010`; ACE NetworkSession.cs:299-304 (server-side emit), no client-consume handler |
 | TS-56 | Chase-camera mouse input retains acdream's invented post-filter yaw/pitch scalars (`0.004`/`0.003` radians per count), and held-key pitch/zoom retain their non-retail integration shapes. Retail mouse look passes `FilterMouseInput(delta) × configured sensitivity × 1/15` as the replacement scale to `CameraSet::Rotate`, which then applies the shared 8° angle; retail held pitch uses the same angle and zoom scales the viewer offset multiplicatively. | `src/AcDream.App/Input/CameraPointerInputController.cs`; `src/AcDream.App/Input/MouseLookController.cs`; `src/AcDream.App/Rendering/CameraFrameController.cs` | Slice 8 is behavior-preserving ownership work. The named-retail audit proves the mismatch but has not yet extracted the configured mouse-sensitivity default or the exact caller flags needed for a complete feel port; changing only one scalar here would create a mixed input model. | RMB/MMB orbit, held pitch, and zoom can feel slower, faster, or differently accelerated than retail even though callback ordering and filtering are correct. | `CameraSet::Rotate @ 0x00458310`; `CameraSet::MouseLookHandler` call at `0x00458EF9`; `CameraSet::Raise @ 0x00457B00`; `CameraSet::Closer @ 0x004586D0`; `docs/research/2026-06-11-holistic-map/wf2-camera-viewer.md` |
 
 ---
@@ -297,7 +298,7 @@ likelihood the guarding assumption breaks). Items below the line are
 phase-gated — they carry their trigger in their row and should land
 WITH that phase, not before.
 
-1. **TS-27 — Retransmit handling** — sole hard blocker for any non-loopback play; failure mode is silent permanent stalls (entities never spawn). Also fix the stale class-doc gap list while there.
+1. **TS-27 — INBOUND retransmit handling** — the outbound sent-packet cache + resend landed with Campaign N Slice N1 (2026-07-29, class-doc gap list fixed same commit); the inbound sequence-aligned ISAAC + client NAK emission (N2/N4) remain the hard blocker for non-loopback play — one lost S2C packet still deafens the session permanently.
 2. **TS-4 — Path-6 steep slide-tangent shortcut** — landing/contact state diverges on every airborne-steep hit; the L.5+ retail-strict followup is already filed with the missing-ingredient analysis.
 3. **UN-1 — CheckOtherCells iteration order** — behavior-bearing halt order with a log-cosmetics justification; trivial to fix (iterate CELLARRAY build order, sort only in probe output).
 4. **TS-1 — PrecipiceSlide stop-at-edge** — visible movement mismatch at every cliff/roof edge; diagnostic already records which ingredient is missing.

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

@@ -251,8 +251,8 @@ verbatim in each implementer prompt.
 
 | Slice | Status | Commit | Notes |
 |---|---|---|---|
-| N0 | complete | `7e9134b4` + the `test(net): N0 fix-up` commit | 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 | pending | — | |
+| 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 | (this slice's commit; SHA recorded at N2 kickoff) | 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. |
 | N2 | pending | — | |
 | N3 | pending | — | |
 | N4 | pending | — | |