fix(chat): CH6a/b rework — grip media, retail window-id model, floaty fixture

Applies docs/research/2026-08-10-ch6ab-review-findings.md in full:

- BLOCKER 1: UiResizeGrip now carries its ElementInfo/resolve pair and
  draws its own authored DirectState media (a synthetic parameterless
  grip still draws nothing, preserving existing resize-drag tests).
  DatWidgetFactory.BuildResizeGrip threads resolve through. All seven
  live grips on the main chat window now resolve a non-zero sprite,
  restoring the visible borders/corners CH6a silently dropped.

- SHOULD-FIX 2: ChatWindowState gains BroadcastTargetWindow, a sentinel
  distinct from every real window id (0-4), fixing the bug where the
  main window's explicit-addressing branch coincided with the broadcast
  check (both were literal 0). SetFilter's main-window no-op is dropped
  — the main window's filter is now genuinely settable. ChatWindowController
  .Bind takes a ChatWindowState (the same canonical instance the floating
  windows already share) and GetTranscriptLines builds a real accept
  predicate instead of accept:null. Verified safe: ClientLocal (0x1A)
  never reaches ChatLog (AddText routes it to the SpewBox and returns),
  so nothing observable regresses.

- SHOULD-FIX 3: UiButton.SuppressSelfToggle stops the four chat-window
  indicator buttons (DAT property 0x0B=true, no retail click handler)
  from flipping their own Selected mirror on a stray click.

- SHOULD-FIX 4: generated and committed chat_floaty_2100005b.json from
  the real installed dats; added the permanent RetailLayoutFixtureGenerator
  entry. All three flagged FloatingChatWindowController assumptions
  (input field, title bar, close button) are confirmed correct against
  real data — no controller code changes needed. New finding: unlike the
  main window, ALL EIGHT floaty border/corner elements are live Type-9
  grips (the floaty's own title bar is its move handle), so a floaty
  window resizes from every edge and corner.

- SHOULD-FIX 5: register row AP-189 documents the shared-500-entry/
  200-line-tail vs retail's per-window 10,000-line scrollback depth gap.

- NITs 1-5: documented the filter-persistence-only-on-/saveautoui
  asymmetry and the reconnect-preserves-filters intent; corrected the
  research doc's modifier-mask mislabel and the "ONLY function" false
  superlative; moved WrapText off ChatWindowController onto
  ChatTranscriptRenderer, closing the circular dependency.

Full Release suite: 12,420 passed / 4 skipped / 0 failed (baseline
12,392/4/0 at 22020ef2; net +28 tests, zero regressions).

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

tests/AcDream.App.Tests/UI/UiButtonTests.cs

@@ -90,6 +90,34 @@ public class UiButtonTests
         Assert.Equal("Highlight", b.ActiveState);
     }
 
+    [Fact]
+    public void SuppressSelfToggle_PressReleaseDoesNotFlipSelected()
+    {
+        // CH6a/b REJECT-review SHOULD-FIX 3: the chat-window 1-4 indicators
+        // (0x10000522-0x10000525) carry DAT property 0x0B (ToggleBehavior) =
+        // true — same shape as ToggleRelease_SelectsHighlightState above —
+        // but retail's own click dispatch has no case for their element ids
+        // (gmMainChatUI::ListenToElementMessage @0x004CDA80), so a click must
+        // NOT flip their Selected mirror. Only SetIndicatorOpen (an external
+        // writer) may change it.
+        var info = ButtonInfo("Normal", "Highlight");
+        AddBoolProperty(info, 0x0Bu, true);
+        var b = CreateButton(info);
+        b.SuppressSelfToggle = true;
+
+        b.OnEvent(new UiEvent(0, b, UiEventType.MouseDown, Data1: 5, Data2: 5));
+        b.OnEvent(new UiEvent(0, b, UiEventType.MouseUp, Data1: 5, Data2: 5));
+
+        Assert.False(b.Selected);
+        Assert.Equal("Normal", b.ActiveState);
+
+        // The external mirror path still works — SuppressSelfToggle only
+        // blocks the self-click, not a producer's own write.
+        b.Selected = true;
+        Assert.True(b.Selected);
+        Assert.Equal("Highlight", b.ActiveState);
+    }
+
     [Fact]
     public void DisabledProperty_SelectsGhostedAndSuppressesClick()
     {