chore: sentry and nextjs major bumps (#633)

* chore: remove nextjs-config

* build fix

* sentry update

* nextjs update

* feature flags doc

* update readme

* explicit nextjs env vars + remove feature-unrelated things and obsolete vars from config

* full config removal

* remove force-dynamic from pages

* compile fix

* restore claude-deleted tests

* no sentry backward compat

* better .env.example

* AUTHENTIK_REFRESH_TOKEN_URL not so required

* accommodate auth system to requiredLogin feature

---------

Co-authored-by: Igor Loskutov <igor.loskutoff@gmail.com>

www/app/lib/features.ts

@@ -11,11 +11,11 @@ export type FeatureName = (typeof FEATURES)[number];
 export type Features = Readonly<Record<FeatureName, boolean>>;
 
 export const DEFAULT_FEATURES: Features = {
-  requireLogin: false,
+  requireLogin: true,
   privacy: true,
-  browse: false,
-  sendToZulip: false,
-  rooms: false,
+  browse: true,
+  sendToZulip: true,
+  rooms: true,
 } as const;
 
 function parseBooleanEnv(