fix(chat): CH6c review fixes — opaque default, opacity-transition register clauses

BLOCKER: ChatSettings.DefaultOpacity shipped retail's base ChatInterface
value (0.5) as ONE shared global default applied to every
RetailWindowManager-registered window, not just the four floating chat
windows retail itself fades. That faded the whole out-of-box registered
UI (radar, vitals, toolbar, main chat, ...) to 50% opacity, including
several windows that can never take keyboard focus and so were stuck at
0.5 permanently. Fixed to gmMainChatUI's 1.0/1.0 override
(0x004CD0F0) instead — retail-identical opaque presentation for the 11
non-chat windows and the main chat window; only the four floating chat
windows now diverge from retail's 0.5-while-idle default, and the
Settings -> Chat transparency slider remains fully user-settable.

AP-190 reworded and gains two new decomp-verified clauses: (3) retail
eases opacity toward its target by 5% of the delta per tick
(ChatInterface::ListenToGlobalMessage @0x004F3840, armed from the focus
element-messages at @0x004F5275) where acdream snaps -- deferred, needs
a UI frame-tick hook the opacity controller doesn't have; (4) retail's
focus predicate is the chat ENTRY FIELD specifically
(ChatInterface::IsTextEntryFocused @0x004F30A0) where acdream uses
any-focusable-descendant. Both findings + the pre-existing UiMenu.cs
PushAlphaAbsolute(1f) popup bypass are folded into the window-shell
research doc's opacity section.

NITs: fixed the stale "text bypasses the alpha" comment in
UiElement.DrawSelfAndChildren (CH6c already routed DrawStringDat/
DrawString through the same ApplyAlpha chokepoint as sprites/rects);
added RetailWindowManager.WindowUnregistered + wired
RetailWindowOpacityController to detach and forget a window unregistered
while it held focus (previously only Dispose detached, leaking any
window unregistered mid-focus for the rest of the session); added
post-Dispose no-op guards to the three Set* opacity mutators; added a
DrawString (BitmapFont path) alpha regression test and a DrawStringDat
outline/background-pass alpha test (the existing tests only ever
exercised the foreground/fill pass).

Also fixes RuntimeSettingsControllerTests.SettingsViewModelSavePreserves
SectionAndTargetOrder's now-stale "target-chat-opacity:0.5:1" expectation
(caught by the full-suite run this fix requires) to match the new 1.0
default.

Campaign ledger CH6c row updated to APPROVE-WITH-FIXES.

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

docs/plans/2026-08-09-chat-parity-campaign.md

@@ -287,7 +287,7 @@ implementer per slice against a pinned contract (per
 | Jump-in-air root cause (round-2 item 1, resolved) | `a5a7eb4f` | Runtime tests 1,323/0 | — | round-3 probe evidence pinpointed a missing `OnInterfaceText` wire on the production controller-commit path (`RuntimeLocalPlayerMovementState.CommitRuntimeOwnedController`); FIXED, regression test added |
 | User gate round 3 | `98de4f5a` | Debug (all projects): 12,329 passed / 4 skipped / 1 failed (pre-existing #351 Debug-only flake — reproduces identically on the pristine pre-round-3 commit, not a regression); Release (every project reachable while a live `AcDream.App.exe` client — PID 15064, must not be killed per project policy — holds its own Release binaries locked, blocking `AcDream.App`/`AcDream.App.Tests`/`AcDream.Core.Tests` specifically): `AcDream.UI.Abstractions.Tests` (the layer this round's `/help` fix lives in) 867/867, plus `Core.Net.Tests` 823/823, `Runtime.Tests` 1,323/1,323, `Content.Tests` 130/130, `Headless.Tests` 89/89, `Bake.Tests` 15/15, `Cli.Tests` 4/4 — all 0 failed | — | findings (a)-(c) fixed this commit — SpewBox flush-top + retail dat font, `/help`/`/help death` exact retail print sequence (see "User gate — round 3" below) |
 | CH6b floating windows 1–4 | `22020ef2`, reworked `1aa77099` | 12,420 passed / 4 skipped / 0 failed | REJECT (docs/research/2026-08-10-ch6ab-review-findings.md) → reworked `1aa77099` — SHOULD-FIXES 2/3/4/5 + NITs 1-5 applied | pending — no client launches this session (hard constraint); needs the next connected round for keybind/mirror/filter visual confirmation, plus the new 0x2100005B fixture's resolved-type assumptions |
-| CH6c opacity | `a819687c` | 12,459 passed / 4 skipped / 0 failed | pending (no subagent review pass this session — implementer-only) | pending — needs the next connected round for visual confirmation (window fade on focus change, Settings slider live-apply) |
+| CH6c opacity | `a819687c` | 12,459 passed / 4 skipped / 0 failed | APPROVE-WITH-FIXES; fixed this commit — BLOCKER (out-of-box `DefaultOpacity` 0.5→1.0), AP-190 reworded + two new decomp-verified clauses (retail's per-tick ease, retail's entry-field-specific focus predicate), NITs (`UiElement.cs` stale comment, `WindowUnregistered` detach, post-Dispose `Set*` guards, `DrawString`/outline-pass alpha tests) | pending — needs the next connected round for visual confirmation (window fade on focus change, Settings slider live-apply) |
 
 ### CH4 closeout (2026-08-09)