feat(themes): apply theme typography font-size overrides on every activation path

HellionChat/Themes/ThemeRegistry.cs

@@ -47,6 +47,12 @@ public sealed class ThemeRegistry
     public Theme? EditingThemeBuffer => _editingThemeBuffer;
     public event Action? OnEditingBufferChanged;
 
+    // Fired after _active changes (Switch / RefreshActiveIfStale); the init host
+    // wires it to the font-atlas rebuild. NOT fired by SwitchSilent (boot handles that).
+    private Action? _onActiveChanged;
+
+    internal void SetActiveChangedCallback(Action callback) => _onActiveChanged = callback;
+
     // Shared slug guard for any code path that turns a slug into a filename.
     // Both SaveEditingBuffer (F1) and ImportFromPath (M6) call this so the
     // path-traversal/invalid-char rules live in exactly one place.
@@ -190,27 +196,32 @@ public sealed class ThemeRegistry
             _active = builtin;
             _active.RecomputeAbgrCache();
             _activeCustomPath = null;
-            return;
         }
-
-        var customTheme = LoadCustomBySlug(slug, out var customPath);
-        if (customTheme is not null)
+        else
         {
-            _active = customTheme;
-            // Defensive — ensures any future theme source always gets a populated cache.
-            _active.RecomputeAbgrCache();
-            _activeCustomPath = customPath;
-            // Force a first-tick reload-check after the switch so the stamp
-            // baseline is established on the next RefreshActiveIfStale call.
-            _lastActiveStamp = DateTime.MinValue;
-            return;
+            var customTheme = LoadCustomBySlug(slug, out var customPath);
+            if (customTheme is not null)
+            {
+                _active = customTheme;
+                // Defensive — ensures any future theme source always gets a populated cache.
+                _active.RecomputeAbgrCache();
+                _activeCustomPath = customPath;
+                // Force a first-tick reload-check after the switch so the stamp
+                // baseline is established on the next RefreshActiveIfStale call.
+                _lastActiveStamp = DateTime.MinValue;
+            }
+            else
+            {
+                // Fallback: neither built-in nor custom matched. Drop to default
+                // and clear the active custom path so RefreshActiveIfStale stays idle.
+                _active = _builtIns[DefaultSlug];
+                _active.RecomputeAbgrCache();
+                _activeCustomPath = null;
+            }
         }
 
-        // Fallback: neither built-in nor custom matched. Drop to default
-        // and clear the active custom path so RefreshActiveIfStale stays idle.
-        _active = _builtIns[DefaultSlug];
-        _active.RecomputeAbgrCache();
-        _activeCustomPath = null;
+        // Notify listeners (the init host wires the font-atlas rebuild here).
+        _onActiveChanged?.Invoke();
     }
 
     // SwitchSilent is the plugin-load init path -- identical to Switch
@@ -426,6 +437,9 @@ public sealed class ThemeRegistry
                 {
                     reloaded.RecomputeAbgrCache();
                     _active = reloaded;
+                    // Same-slug save bypasses Switch's notify (it noop'd on same slug);
+                    // fire here so a typography change applies (no-op if size unchanged).
+                    _onActiveChanged?.Invoke();
                 }
             }
 
@@ -568,6 +582,7 @@ public sealed class ThemeRegistry
         // RecomputeAbgrCache happens inside RefreshCustomCache on cache miss.
         var reloaded = Get(_active.Slug);
         _active = reloaded;
+        _onActiveChanged?.Invoke();
     }
 
     // 0x80070020 = SHARING_VIOLATION, 0x80070021 = LOCK_VIOLATION.

HellionChat/Themes/ThemeTypography.cs

@@ -1,6 +1,7 @@
 namespace HellionChat.Themes;
 
 // Optional per-theme; reserved as an extension point for future theme slots.
+// Italic body-size override intentionally omitted (v1.9.0 Typography-Polish).
 public sealed record ThemeTypography(
     float? OverrideGlobalFontSizePt = null,
     float? OverrideSymbolsFontSizePt = null