refactor: stricter domain: theme

toju-app/src/app/domains/theme/infrastructure/util/theme-storage.util.ts

@@ -0,0 +1,41 @@
+import { STORAGE_KEY_THEME_ACTIVE, STORAGE_KEY_THEME_DRAFT } from '../../../../core/constants';
+
+export interface ThemeStorageSnapshot {
+  activeText: string | null;
+  draftText: string | null;
+}
+
+function readStoredThemeText(key: string): string | null {
+  try {
+    const raw = localStorage.getItem(key);
+
+    return typeof raw === 'string' && raw.length > 0
+      ? raw
+      : null;
+  } catch {
+    return null;
+  }
+}
+
+function writeStoredThemeText(key: string, value: string): void {
+  try {
+    localStorage.setItem(key, value);
+  } catch {
+    /* storage can be unavailable in private contexts */
+  }
+}
+
+export function loadThemeStorageSnapshot(): ThemeStorageSnapshot {
+  return {
+    activeText: readStoredThemeText(STORAGE_KEY_THEME_ACTIVE),
+    draftText: readStoredThemeText(STORAGE_KEY_THEME_DRAFT)
+  };
+}
+
+export function saveActiveThemeText(text: string): void {
+  writeStoredThemeText(STORAGE_KEY_THEME_ACTIVE, text);
+}
+
+export function saveDraftThemeText(text: string): void {
+  writeStoredThemeText(STORAGE_KEY_THEME_DRAFT, text);
+}