fix(CT-GF1): review fix round — literal DrawHere clip shape, empty-clip cull, popup input routing

Applies all 11 items from the Opus dual-lens review of 989f6652 (0
blockers, 7 SHOULD-FIX, 4 NOTE):

- S2: UiElement.DrawSelfAndChildren now pushes the ambient clip right
  after PushAlpha and wraps OnDraw + the children walk +
  OnDrawAfterChildren in ONE block — the literal UIRegion::DrawHere
  @0x0069FA30 shape, which clips an element's OWN DrawSelf too, not
  just its children (UIElement_Text::DrawSelf @0x00467AA0 locks glyph
  blits to its own clipped surface rect; UIRegion::DrawSelf
  @0x0069F1A0 blits per clip rect). Deleted the two now-redundant
  ad-hoc self-clips this supersedes: UiText.DrawText and
  UiField.DrawMultiLine both pushed their own (0,0,Width,Height) —
  exactly what the new ambient clip already provides one level up.
  Kept UiButton.DrawBlockLabel's clip: it clips to LabelBox/ValueBox,
  an authored INNER sub-rect that can be smaller than and offset from
  the button's own full rect — a genuine narrower viewport, not a
  redundant duplicate.
- S3: deleted UiItemList's `ClipsChildren => CellWidth > 0f` override
  — correct under the old opt-in-false default, inverted under the
  new default-true (an unconfigured list would stop clipping instead
  of clipping like everything else).
- S4: pinned the escaped-popup input path end to end. New
  UiAncestorClipTests test mounts a menu inside a short window on a
  real UiRoot, opens it, and proves a click in the escaped popup
  region reaches the menu through UiRoot.PopupHit (a plain top-down
  walk is proven to reject the same point first). UiRoot.WantsMouse
  now also checks PopupHit — it previously only checked Captured/
  HitTestTopDown, so a game action could fire underneath an open
  dropdown's escaped region. OnMouseDown/OnScroll already routed
  through PopupHit first (#374); unchanged.
- S5: strengthened the Titles-divider regression test's positive
  half. The old assertion only checked SOME quad's Y fell in a band —
  vacuously true given other same-band content. Now asserts the
  divider's exact rect (X and Y), then diffs against the same rect
  with the divider hidden (Visible=false) to prove the quad was
  actually attributable to it.
- S1: added UiWindowDrawCaptureSweepTests — Character/Chat/Vendor/
  Options mounted through their real production Bind entry points
  with a non-zero sprite resolver, drawn via RecordingGpuDevice,
  asserting a per-window vertex floor (~40-45% of this session's
  observed baseline: Character 588, Chat 162, Vendor 54, Options 240)
  plus one key sprite id read LIVE off the bound controller/element
  (never hardcoded). Character's key sprite (RetailChromeSprites.
  TopEdge) specifically exercises OnDrawAfterChildren, the exact path
  S2's caution note flagged. Inventory/Paperdoll/social/map-house
  skipped — no single fixture-driven top-level Bind entry point.
- S6: added the CT-GF1 subsection to the campaign plan's ledger
  (989f6652 + this fix round; CT7 re-gate still owed).
- S7: UiRenderContext.PushClipUnbounded now resets to the CANVAS rect
  (0,0,ScreenSize), not null — retail's own popup region is
  SCREEN-clipped (UIElement_Menu::MakePopup spawns a top-level region
  bounded by the screen), not truly unbounded. AD-113 amended.
- N1: UiRoot overrides ClipsChildren => false — the root's own region
  IS the screen (the viewport already scissors it), so this is a
  safety net against a momentarily zero-sized root silently blanking
  the whole UI tree under the new ancestor-clip default.
- N2: added the empty-clip subtree cull (retail's var_24 gate
  @0x0069FB8E) to DrawSelfAndChildren only — DrawOverlays is a wholly
  separate traversal untouched by this change. New test proves a menu
  inside a fully-clipped (zero-width) window still draws its open
  popup via the overlay pass while the main pass draws nothing.
- N3: CT7 script §5 now names the collapsed-toolbar check and the
  four highest-overflow windows (combat/vitals bar, Options
  bottom-button row, map/house page, floaty chat) as explicit
  eyeball items for the re-gate.
- N4: verification below covers both the working tree and the clean
  committed tree.

Decomp anchors: UIRegion::DrawHere @0x0069FA30 (var_24 gate
@0x0069FB8E); UIElement_Text::DrawSelf @0x00467AA0 (self-clip);
UIRegion::DrawSelf @0x0069F1A0; UIElement_Menu::MakePopup (screen-
clipped popup region).

Verification (both runs green, --filter "Lane!=InstalledDat&
Lane!=PreparedPackage&Lane!=Live&Lane!=Manual&Lane!=Timing&
Lane!=Windows&Lane!=Linux&Lane!=SystemFont&Purpose!=Diagnostic&
Status!=KnownFailure"): full Release solution build green; working
tree 14,900+ tests across every project (one LandblockPresentation
PipelineTests flake reproduced ONLY under full-solution parallel
load, passes standalone and on rerun — unrelated to this change,
streaming domain); InstalledDat lane green (ACDREAM_RUN_INSTALLED_DAT
_TESTS=1, Status!=KnownFailure, 205+34+3+172 App/Content/Bake/Core
tests). Clean committed tree (git stash push -u the uncommitted
owner probe + docs files, rerun, stash pop) reported in the session
summary.

src/AcDream.App/UI/UiRoot.cs carries an unrelated, pre-existing
uncommitted owner probe (ACDREAM_PROBE_UI_HOVER) — staged selectively
(git add -p) so only this commit's own two hunks (ClipsChildren
override, WantsMouse) landed; the probe hunk is untouched and stays
uncommitted, same as before this fix round.

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

src/AcDream.App/UI/UiRenderContext.cs

@@ -116,18 +116,34 @@ public sealed class UiRenderContext
     }
 
     /// <summary>
-    /// Discard every inherited clip rect for the duration of one overlay draw —
-    /// the escape hatch <see cref="UiElement.ExpandsClipForPopup"/> uses so a popup
-    /// drawn inline from its owning widget (see that property's doc comment for the
-    /// retail-parity rationale) is not wrongly clipped by the ancestor chain the
-    /// CT-GF1 default clip (<see cref="UiElement.ClipsChildren"/>) now threads through
-    /// every other element. Shares <see cref="PopClip"/>'s stack, so pair the two
-    /// exactly like <see cref="PushClip"/>.
+    /// True when the current accumulated clip is non-null and has zero (or negative)
+    /// area — CT-GF1 fix-round subtree cull, porting retail's
+    /// <c>UIRegion::DrawHere</c> <c>var_24</c> gate @0x0069FB8E: an empty intersected
+    /// clip skips <c>EraseSelf</c>/<c>DrawChildren</c>/<c>DrawSelf</c> for the whole
+    /// subtree, not just individual draw calls (those already no-op against an empty
+    /// clip via <see cref="ClipRect"/>/<see cref="UiClipRect.TryClipSprite"/> — this
+    /// additionally skips the WALK). A null clip (nothing pushed yet, or reset via
+    /// <see cref="PushClipUnbounded"/>) is NOT empty — it means unbounded, so this is
+    /// false in that case.
+    /// </summary>
+    public bool CurrentClipIsEmpty => _clip is { } c && c.IsEmpty;
+
+    /// <summary>
+    /// Reset the accumulated clip to the full CANVAS rect (0,0,ScreenSize) for the
+    /// duration of one overlay draw — the escape hatch <see cref="UiElement.ExpandsClipForPopup"/>
+    /// uses so a popup drawn inline from its owning widget (see that property's doc
+    /// comment for the retail-parity rationale) is not wrongly clipped by the
+    /// ancestor chain the CT-GF1 default clip (<see cref="UiElement.ClipsChildren"/>)
+    /// now threads through every other element. Retail's own popup region is still
+    /// SCREEN-clipped (<c>UIElement_Menu::MakePopup</c> spawns a top-level region
+    /// bounded by the screen, not truly infinite) — this is the canvas rect, not
+    /// <c>null</c>/unbounded, matching that. Shares <see cref="PopClip"/>'s stack, so
+    /// pair the two exactly like <see cref="PushClip"/>.
     /// </summary>
     public void PushClipUnbounded()
     {
         _clipStack.Add(_clip);
-        _clip = null;
+        _clip = new UiClipRect(0f, 0f, ScreenSize.X, ScreenSize.Y);
     }
 
     /// <summary>Route subsequent draws to the overlay layer (flushed on top of the whole