fix(layout): four axes that could always stale the cache, and the new roles

The height cache keys on a fingerprint of everything that can change a row's
height. Four things that can were never in it:

- ItalicFontV2.SizePt. ChunkRenderer pushes the italic face mid-row for emphasis,
  so there have been mixed sizes in a single line all along -- nobody called it
  that. Changing only the italic size moved every wrapped row and left the cache
  untouched.
- ItalicEnabled, which swaps between ItalicFont at its own size and AxisItalic at
  the base size.
- FontsEnabled and UseHellionFont, which swap the face outright. This pair is the
  quiet one: both size fields default to 12.75f, so the fingerprint did not move
  at all while the glyph widths underneath it did.

On top of those, the two new role sizes. They follow the base arithmetically, but
the resolved value is what belongs in the fingerprint -- a theme override moves
the base without moving any factor.

The three toggles go in the discrete half so they bypass the settle window, the
same way density already does. The sizes are sliders and wait it out.

Falsified rather than assumed: dropping FontsEnabled back out of Discrete turns
the new test red, so it is measuring the axis and not just passing.

HellionChat/Ui/Components/MessageList.cs

@@ -93,13 +93,25 @@ internal sealed class MessageList
     // Width is passed in (ContentRegionAvail is only valid inside the draw child);
     // enum modes widened to int so the record stays comparable. UiScale is in here
     // because it feeds CalcWordWrapPositionA -- a scale change rewraps every row.
+    //
+    // v1.13.0 added four axes that could always stale this cache and never did:
+    // the italic size (pushed mid-row by ChunkRenderer), ItalicEnabled (which
+    // swaps between two differently sized faces), FontsEnabled and UseHellionFont
+    // (both swap the face outright, and their two size fields default to the same
+    // 12.75f -- so the fingerprint did not move while the glyph widths did).
     private LayoutFingerprint BuildLayoutFingerprint(float contentWidth)
     {
-        var (global, symbols) = _fonts.EffectiveFontFingerprint();
+        var fonts = _fonts.EffectiveFontFingerprint();
         return new LayoutFingerprint(
-            global,
-            symbols,
+            fonts.Global,
+            fonts.Symbols,
+            fonts.Sender,
+            fonts.Meta,
+            fonts.Italic,
             Plugin.Config.UseCompactDensity,
+            Plugin.Config.FontsEnabled,
+            Plugin.Config.UseHellionFont,
+            Plugin.Config.ItalicEnabled,
             (int)Plugin.Config.NameFormMode,
             (int)Plugin.Config.WorldSuffixMode,
             contentWidth,