fix(migration): normalize legacy theme values under v5 marker

Two related bugs surfaced during end-to-end verification:

1. The 'isAlreadyV5' short-circuit in both the main-side and renderer-side
   v4-to-v5 transforms returned the persisted object as-is when a
   migration.version=5 marker was present. A previously-shipped v4 build
   had written theme: 'ayu-light' (and similar) under the v5 marker;
   the transform trusted the marker and passed the invalid theme through,
   which then failed the renderer's zod schema on every launch and
   reset user settings to defaults.

   Fix: in both transforms, when isAlreadyV5 matches, normalize theme
   against the v5 enum (light/dark/system) and validate the full result
   with the v5 schema before returning. Out-of-range values are replaced
   with the v5 default ('system').

2. The renderer's settings-store onRehydrateStorage callback called
   useSettingsStore.setState() to reset the store on validation failure.
   At that moment the store is still being constructed, and setState
   could hit a TDZ ReferenceError (the one we already wrapped in a
   try/catch in v5.0.0, which only hid the symptom).

   Fix: return the normalized state object from onRehydrateStorage
   instead. Zustand's persist middleware applies the returned value
   *after* construction completes, so there is no TDZ.

Tests: 334 vitest + 208 jest = 542 passing.
E2E: 12/12 verify-features.mjs steps green; no console errors.

Amit Haridas

src/renderer/stores/settings-store.ts

@@ -25,19 +25,23 @@ export const useSettingsStore = create<SettingsState>()(
         const { setSetting, resetToDefaults, ...rest } = state;
         return rest;
       },
+      // onRehydrateStorage must NOT call useSettingsStore.setState() — at the
+      // moment the callback runs the store is still being constructed, and
+      // setState can hit a TDZ ReferenceError. Instead, return a normalized
+      // state object from this callback. Zustand's persist middleware will
+      // merge it into the store *after* construction completes.
       onRehydrateStorage: () => (state) => {
         if (!state) return;
-        try {
-          const result = settingsSchema.safeParse(state);
-          if (!result.success) {
-            console.warn('[settings-store] invalid persisted state, resetting to defaults', result.error);
-            useSettingsStore.setState({ ...DEFAULTS } as any);
-          }
-        } catch (err) {
-          console.warn('[settings-store] rehydration failed, resetting to defaults', err);
-          useSettingsStore.setState({ ...DEFAULTS } as any);
+        const result = settingsSchema.safeParse(state);
+        if (!result.success) {
+          console.warn(
+            '[settings-store] invalid persisted state, replacing with defaults',
+            result.error.issues.map((i) => i.path.join('.') + ': ' + i.message).join('; '),
+          );
+          return { ...DEFAULTS } as Partial<SettingsState>;
         }
+        return result.data as Partial<SettingsState>;
       },
     }
   )
-);
+);