fix(chat): CH3 review fixes — phantom UN-9, allegiance-broadcast echo, /a legacy fallback

Applies the Opus review of Campaign CH slice CH3 (614a1e05):

- B1: UN-9 was a phantom divergence — ACE's CharacterOptions1.cs:47
  OR-sum is 0x50C4A54A (its own comment confirms 1355064650), identical
  to acdream's literal. The wrong 0x50C48D4A existed only in the research
  doc. Row deleted, register §5 reverted to 4 rows, research doc corrected
  with dated notes.
- S1/S4: AllegianceBroadcast (0x02000000) is a server-echoing channel —
  ACE's GameActionChatChannel handler includes the sender in its real-name
  Allegiance.Members broadcast (retail's DoAllegianceBroadcast has no
  AddTextToScroll), so the client must skip its local optimistic echo, not
  keep it. ChatChannelInfo.Legacy.IsSelfEchoChannel() now returns true for
  it; RouteLegacyChannel's comment corrected; Turbine.IsSelfEchoChannel()'s
  backwards comment rewritten truthfully.
- S3: retail's /a stays on the legacy AllegianceBroadcast bitflag until
  StartupTurbineChatSystem successfully starts Turbine chat — "never
  started" (TurbineChatState.Enabled == false) now falls back to legacy in
  both LiveSessionCommandRouter.RouteChat and
  DirectGameRuntimeCommandAdapter.TrySendChannel, while "enabled but no
  allegiance room" still correctly refuses locally.
- S5: added a LiveSessionEventRouter test proving the Options.Replace ->
  OnCharacterOptionsChanged seeding order, and RuntimeSettingsTargets /
  GameWindowLiveSessionOwnershipTests tests proving the concrete
  ICommandBus.Publish wiring and the single LiveSessionCommandSurface
  construction site.
- S6: AP-181 rewritten to name both of retail's omitted pre-send checks
  (IsMessageSafe silent-drop, then IsMessageSpam) and stop misattributing
  either to RouteLegacyChannel, which has no such gates.
- N1-N7: CharacterOptionId moved below SocialActions so its doc comment
  re-attaches; TurbineChatMembershipGate reuses TurbineChatDisplayNames
  instead of a duplicate table; the gate-to-refusal-text mapping is now
  shared via TurbineChatMembershipGate.ResolveRefusalText instead of
  duplicated in both hosts; ChatSettings.Default now matches ACE's real
  CharacterOptions2.Default (Roleplay/Society start off); a doc-comment
  clarifies only the five Hear toggles are server-backed; the register's
  §3 header recounted 129 -> 128.

Suite: 11,964 passed / 4 skipped / 0 failed (baseline 11,957/4/0 + 7 new
tests). Campaign ledger CH3 review column updated to APPROVE-WITH-FIXES.

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

src/AcDream.App/Net/LiveSessionRuntimeFactory.cs

@@ -313,8 +313,13 @@ internal sealed class LiveSessionRuntimeFactory
             OnMovementStatsUpdated: () => _movementStats.Apply("stats"),
             // Campaign CH slice CH3 (2026-08-09): reseed the Settings Chat
             // draft from server truth every time a PlayerDescription lands
-            // (research doc §5.2/§6.4 — the local ChatSettings.Default lied
-            // relative to ACE's CharacterOptions2.Default).
+            // (research doc §5.2/§6.4). N4 (CH3 Opus review, 2026-08-09)
+            // aligned ChatSettings.Default itself to ACE's real
+            // CharacterOptions2.Default, but this reseed stays load-bearing
+            // regardless — a per-character persisted settings.json can
+            // still diverge from server truth (e.g. an older save, or a
+            // character whose allegiance/society changed), and the server
+            // is always authoritative.
             OnCharacterOptionsChanged: (_, options2) =>
                 _interaction.Settings.SyncChatFromServerOptions(options2));
     }