feat(labrinth): user blocking (#6837)

* feat(labrinth): user blocking

still wip, nothing is hooked up

* style(labrinth): cargo fmt

* refactor(labrinth): move block/unblock routes to public api

* feat(labrinth): block friend requests if blocked

* feat(labrinth): remove friend/request on block

* feat(labrinth): get blocked users endpoint

apps/labrinth/migrations/20260722120000_blocked-users.sql

@@ -0,0 +1,5 @@
+CREATE TABLE blocked_users (
+    user_id bigint NOT NULL REFERENCES users (id) ON DELETE CASCADE,
+    blocked_id bigint NOT NULL REFERENCES users (id) ON DELETE CASCADE,
+    PRIMARY KEY (user_id, blocked_id)
+);