Updates Apr3: new pages, components, and widespread UI/API improvements

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/store/themeStore.ts

@@ -0,0 +1,32 @@
+import { create } from 'zustand'
+import { persist } from 'zustand/middleware'
+
+interface ThemeState {
+  isDark: boolean
+  toggle: () => void
+}
+
+export const useThemeStore = create<ThemeState>()(
+  persist(
+    (set) => ({
+      isDark: false,
+      toggle: () => set((s) => {
+        const next = !s.isDark
+        document.documentElement.classList.toggle('dark', next)
+        return { isDark: next }
+      }),
+    }),
+    { name: 'theme' }
+  )
+)
+
+/** Call once at app startup to apply persisted theme class */
+export function initTheme() {
+  const raw = localStorage.getItem('theme')
+  if (raw) {
+    try {
+      const parsed = JSON.parse(raw) as { state?: { isDark?: boolean } }
+      document.documentElement.classList.toggle('dark', !!parsed.state?.isDark)
+    } catch { /* ignore */ }
+  }
+}