fix: sync context panel iframe themes

Keeps embedded sessions aligned with parent theme
Prevents iframe reloads on theme changes
Supports theme hotkeys from focused iframes

packages/ui/src/stores/useUIStore.ts

@@ -351,6 +351,7 @@ const upsertContextPanelTab = (
           dedupeKey: nextTab.dedupeKey,
           label: nextTab.label,
           stagedDiff: nextTab.stagedDiff,
+          readOnly: nextTab.readOnly,
           touchedAt: Date.now(),
         }
       : tab));