feat(chat): Campaign CH slice CH6c — window opacity + transparency setting

Retail's ChatInterface::SetOpacity (0x004F3120) fades the WHOLE composited
window surface with one alpha; UiRenderContext.ApplyAlpha already gated
DrawSprite/DrawRect/DrawFill (since 1da697ec, pre-CH6) but DrawStringDat and
DrawString still passed applyAlpha:false, so text stayed sharp over a
translucent window. Both now route through the same chokepoint.

RetailWindowOpacityController (new) subscribes to a new
RetailWindowManager.WindowRegistered event and drives every registered
window's live Opacity from keyboard-focus state, applied to EVERY window
(chat, floaties, vitals, toolbar, ...) rather than retail's ChatInterface-only
scope — register row AP-190, retiring the stale AP-40 "fixed 0.75, no focus
transition" row in the same commit.

Verified retail's shipped opacity defaults from the decomp (constructor
literals, no cdb needed): the base ChatInterface ctor sets
DefaultOpacity=0.5/ActiveOpacity=1.0, kept unmodified by the four floating
windows; gmMainChatUI's own ctor overrides the main window to 1.0/1.0
(always fully opaque). acdream ships one shared global default (0.5/1.0)
rather than replicating the per-class override — also AP-190. The linking
invariant (raising default above active drags active UP; lowering active
below default drags default DOWN — never a clamp) is ported verbatim as
ChatOpacityLink in AcDream.UI.Abstractions, shared by the live controller
and the new Settings -> Chat tab's two linked opacity sliders.

Persistence: ChatSettings.DefaultOpacity/ActiveOpacity round-trip through
SettingsStore; Save pushes both through IRuntimeSettingsTargets.SetChatOpacity
into the live controller, no restart required.

Rider (CH6a/b re-review): strengthened the grip-media regression guard past
a bare SpriteFile != 0 check — ChatLayoutConformanceTests now drives each
live grip through a real UiRenderContext/TextRenderer (backed by the
in-memory RecordingGpuDevice test double) and asserts the draw call chain
actually queued sprite geometry, via a new TextRenderer.DebugSpriteSegments
test-only accessor.

Full Release suite 12,459 passed / 4 skipped / 0 failed (baseline
12,420/4/0). No subagents, no client launches (session hard constraints);
pending the next connected user gate for visual confirmation.

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

docs/research/2026-08-09-chat-retail-window-shell.md

@@ -463,12 +463,54 @@ and application is one call on the window's own render surface —
 text — with one alpha, not a per-widget background tint.** This is the shape the
 future acdream user setting should take.
 
-UNVERIFIED: retail's *shipped default values* for the two sliders. They are not
-constants in code (the only in-code fallback is 1.0f); they arrive from the
-server's `GameplayOptions` blob or from the options page's authored slider
-defaults. Cheapest resolution: one cdb breakpoint on
-`ChatInterface::SetDefaultOpacity` at login and read `st(0)` — or dump the
-slider template defaults from the options LayoutDesc (`0x2100002B`).
+**RESOLVED at Campaign CH slice CH6c (2026-08-10) by static decomp, not cdb —
+the values are constructor-literal, so no live attach was needed.** Retail's
+shipped defaults are PER WINDOW CLASS, not one constant:
+
+```
+004f4550  ChatInterface::ChatInterface(this, arg2, arg3)      // BASE ctor
+004f459f      this->m_fDefaultOpacity = 0.5f;
+004f45a5      this->m_fCurrentOpacity = 0.5f;
+004f45ab      this->m_fActiveOpacity  = 1f;
+
+004cd0f0  gmMainChatUI::gmMainChatUI(this, arg2, arg3)         // derived, calls base first
+004cd0ff      ChatInterface::ChatInterface(this, arg2, arg3);
+004cd148      this->m_fDefaultOpacity = 1f;                     // OVERRIDES base
+004cd14e      this->m_fCurrentOpacity = 1f;
+                                                                 // m_fActiveOpacity left at base's 1f
+
+004ce2c0  gmFloatyChatUI::Create(arg1, arg2)                   // the 4 floating windows
+004ce2e0      ChatInterface::ChatInterface(eax, arg1, arg2);   // NO override — keeps base 0.5/1.0
+```
+
+`gmFloatyMainChatUI` (element class `0x10000050`, the concrete class actually
+instantiated for the retail main chat window — its `DynamicCast` accepts both
+`0x10000050` and `0x10000041`) calls `gmMainChatUI::gmMainChatUI` as its own
+base constructor (`0x004D22B0`) and adds no opacity override of its own, so it
+inherits `gmMainChatUI`'s 1.0/1.0.
+
+**So: the main chat window is ALWAYS FULLY OPAQUE in both states (Default=1.0,
+Active=1.0) unless a saved `GameplayOptions` value overrides it via
+`UpdateFromPlayerModule`; the four floating windows default to
+Default=0.5/Active=1.0 (translucent when idle, opaque once the chat entry has
+focus).** These are IN-MEMORY CONSTRUCTED starting values for each window
+INSTANCE's fields — they get overwritten the moment `UpdateFromPlayerModule`
+successfully reads a persisted `0x10000080`/`0x10000081` value from
+`PlayerModule::InqOption` (the SAME global option for every window instance),
+which is why the two options are still correctly described as GLOBAL rather
+than per-window: only a NEVER-SAVED option (a fresh character, nothing in the
+`GameplayOptions` blob yet) lets the per-class constructed defaults show
+through, and even then only until the user's first slider drag pushes one
+shared value into every live window via `RecvNotice_GameplayOptionChanged`.
+
+acdream ships ONE shared global default — the base `ChatInterface` value,
+0.5/1.0 — applied uniformly to every window including the main chat window
+(register row AP-190 in `docs/architecture/retail-divergence-register.md`),
+rather than replicating `gmMainChatUI`'s per-class 1.0/1.0 override. The
+linking invariant (active >= default, restored by dragging the OTHER value —
+verified from `SetDefaultOpacity`/`SetActiveOpacity`'s own bodies, matching
+the summary already recorded above) is ported exactly regardless of which
+default seeds it.
 
 ---
 
@@ -635,7 +677,26 @@ per-grip bool properties `0x2A`/`0x2B`/`0x2C`/`0x2D`. Additionally,
 for `Resizebar` in `src/AcDream.App/UI` returns nothing — so authored grips
 would be imported as inert sprites today.
 
-**G3 — Window opacity is completely inert.**
+**G3 — Window opacity is completely inert. CLOSED at Campaign CH slice CH6c
+(2026-08-10).** `UiRenderContext.ApplyAlpha` already gated `DrawRect`/
+`DrawFill`/`DrawSprite` before this slice (added back at `1da697ec`, well
+before CH6 — the "zero consumers" framing below described the PUBLIC
+`AlphaMod` property specifically, not the private `_alpha`/`ApplyAlpha` pair
+those three draws already used); the actual gap was narrower than originally
+scoped: (a) `DrawStringDat`/`DrawString` still passed `applyAlpha: false`, so
+TEXT stayed sharp over a translucent window against retail's whole-surface
+`SetOpacity` semantics — CH6c fixed both; (b) nothing ever SET a window's
+`Opacity` below its 1f default, since `RetailUiRuntime.MountChat` deliberately
+left it at 1f pending this slice. CH6c added
+`RetailWindowOpacityController` (`src/AcDream.App/UI/RetailWindowOpacityController.cs`),
+which drives every `RetailWindowManager`-registered window's live `Opacity`
+from keyboard-focus state and the two retail-linked Default/Active floats,
+now exposed as a Settings → Chat tab transparency slider pair
+(`SettingsPanel.RenderChatTab`). See the verified defaults + linking
+behavior above (§3) and register row AP-190. The original paragraph below is
+kept verbatim as the historical record of what CH6a/b actually shipped —
+do not re-run this investigation.
+
 `RetailWindowFrame.cs:157` sets `outerFrame.Opacity`, and
 `UiElement.DrawSelfAndChildren` (`src/AcDream.App/UI/UiElement.cs:465`) and
 `DrawOverlays` (`:513`) push it onto `UiRenderContext`'s alpha stack. But
@@ -743,8 +804,16 @@ run alongside either.
 
 - **Retires** any row asserting "chat window is not resizable from the top" once
   CH6a lands.
-- **New row** if CH6b keeps text out of the window alpha (retail's
-  `ChatInterface::SetOpacity @0x004F3120` fades the whole surface).
+- **CLOSED at CH6c**: text now respects window alpha — `DrawStringDat`/
+  `DrawString` route through `ApplyAlpha` exactly like `DrawSprite`/`DrawRect`/
+  `DrawFill`, matching `ChatInterface::SetOpacity`'s whole-surface fade. No
+  divergence row needed for this part.
+- **New row AP-190** (CH6c): acdream applies the two opacity options to EVERY
+  `RetailWindowManager` window (chat + floaties + vitals + toolbar +
+  everything else), where retail's mechanism only ever runs from
+  `ChatInterface`-derived windows; and ships ONE shared default (the base
+  `ChatInterface` ctor's 0.5/1.0) rather than `gmMainChatUI`'s per-class
+  1.0/1.0 override for the main window specifically.
 - **New row** for local-only chat-window persistence until CH6f, since retail
   stores this server-side in `GameplayOptions`.