fix: grant admin role to anonymous user and add DEFAULT_TOOL_VIEW env var

When AUTH_ENABLED=false, the anonymous user was assigned the "user" role
which lacks settings:write permission, making all settings saves return
403. Since no admin exists when auth is disabled, settings were
permanently read-only. Promote the anonymous user to "admin" so the
single user has full control of the instance.

Also adds DEFAULT_TOOL_VIEW env var (sidebar|fullscreen) following the
existing DEFAULT_THEME pattern, seeded via ensureDefaultSettings() on
first boot.

Closes #135

apps/api/src/index.ts

@@ -63,6 +63,7 @@ function ensureDefaultSettings() {
   const defaults: Record<string, string> = {
     defaultTheme: env.DEFAULT_THEME,
     defaultLocale: env.DEFAULT_LOCALE,
+    defaultToolView: env.DEFAULT_TOOL_VIEW,
   };
   for (const [key, value] of Object.entries(defaults)) {
     const existing = db.select().from(schema.settings).where(eq(schema.settings.key, key)).get();