fix(settings): validate seasonalThemeOverride; commit page zoom on blur; GIF picker opt-in

- seasonalThemeOverride is coerced to 'auto' when the persisted value is
  outside the union, like every other enum setting (tested).
- PageZoomInput commits on blur as well as Enter.
- New gifPickerEnabled setting (default off) with a disclosure that GIF
  searches go to Giphy; the picker doesn't mount and the composer button
  is hidden while off.

Fixes #74
Fixes #75
Fixes #68

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/state/settings.test.ts

@@ -56,6 +56,18 @@ test('coerces unknown persisted denoise model / ringtone id back to defaults', (
   assert.equal(valid.ringtoneId, 'chime');
 });
 
+test('coerces unknown persisted seasonalThemeOverride back to auto', () => {
+  setStored(null);
+  const defaults = getSettings();
+  assert.equal(defaults.seasonalThemeOverride, 'auto');
+
+  setStored(JSON.stringify({ seasonalThemeOverride: 'retired-theme' }));
+  assert.equal(getSettings().seasonalThemeOverride, 'auto');
+
+  setStored(JSON.stringify({ seasonalThemeOverride: 'earthday' }));
+  assert.equal(getSettings().seasonalThemeOverride, 'earthday');
+});
+
 test('merges stored values over defaults', () => {
   setStored(JSON.stringify({ callNoiseSuppression: 'off', someUnknownKey: 1 }));
   const s = getSettings();

src/app/state/settings.ts

@@ -25,6 +25,38 @@ export type DenoiseModelId = 'rnnoise' | 'speex' | 'dtln' | 'deepfilternet';
 // 'soft' / 'retro' are synthesized in-browser (see utils/ringtones.ts);
 // 'none' is silent (visual-only incoming-call UI).
 export type RingtoneId = 'classic' | 'chime' | 'soft' | 'retro' | 'none';
+
+export type SeasonalThemeOverride =
+  | 'auto'
+  | 'off'
+  | 'halloween'
+  | 'christmas'
+  | 'newyear'
+  | 'autumn'
+  | 'aprilfools'
+  | 'lunar'
+  | 'valentines'
+  | 'stpatricks'
+  | 'earthday'
+  | 'deepspace'
+  | 'arcade';
+
+// Allow-list used to validate persisted values below.
+const SEASONAL_THEME_OVERRIDES: SeasonalThemeOverride[] = [
+  'auto',
+  'off',
+  'halloween',
+  'christmas',
+  'newyear',
+  'autumn',
+  'aprilfools',
+  'lunar',
+  'valentines',
+  'stpatricks',
+  'earthday',
+  'deepspace',
+  'arcade',
+];
 // [P5-31] Granular call quality caps. 'auto' = don't cap (the EC fork keeps its
 // default encoding). Numbers are kbps (audio/screenshare bitrate) or fps
 // (screenshare framerate); converted to the fork's bits/sec + fps payload in
@@ -254,24 +286,15 @@ export interface Settings {
   soundboardEnabled: boolean;
   soundboardVolume: number; // 0–100
 
-  seasonalThemeOverride:
-    | 'auto'
-    | 'off'
-    | 'halloween'
-    | 'christmas'
-    | 'newyear'
-    | 'autumn'
-    | 'aprilfools'
-    | 'lunar'
-    | 'valentines'
-    | 'stpatricks'
-    | 'earthday'
-    | 'deepspace'
-    | 'arcade';
+  seasonalThemeOverride: SeasonalThemeOverride;
 
   // On-device message translation
   translateTargetLang: string; // BCP-47 base code, default 'en'
   autoTranslate: boolean; // auto-translate incoming foreign messages (opt-in)
+
+  // GIF picker sends every search term (and the user's IP) directly to Giphy,
+  // so it's opt-in and off by default.
+  gifPickerEnabled: boolean;
 }
 
 const defaultSettings: Settings = {
@@ -374,6 +397,8 @@ const defaultSettings: Settings = {
 
   translateTargetLang: 'en',
   autoTranslate: false,
+
+  gifPickerEnabled: false,
 };
 
 export const getSettings = (): Settings => {
@@ -422,6 +447,12 @@ export const getSettings = (): Settings => {
         typeof saved.autoTranslate === 'boolean'
           ? saved.autoTranslate
           : defaultSettings.autoTranslate,
+      // Coerce any unknown/retired persisted seasonal theme id back to 'auto'.
+      seasonalThemeOverride: SEASONAL_THEME_OVERRIDES.includes(
+        saved.seasonalThemeOverride as SeasonalThemeOverride,
+      )
+        ? (saved.seasonalThemeOverride as SeasonalThemeOverride)
+        : defaultSettings.seasonalThemeOverride,
       composerToolbarButtons: {
         ...DEFAULT_COMPOSER_TOOLBAR,
         ...(saved.composerToolbarButtons ?? {}),