fix: collection name mismatch, login/register navigation, and connection config

- Fix teamSessions → team_sessions to match PocketBase collection name
- Replace <a @click> with <router-link> in Login and Register views
- Update PocketBase default URL and vite proxy target
- Comment out docker-compose user directive for permission fix

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/api/pocketbase.ts

@@ -1,7 +1,7 @@
 // src/api/pocketbase.ts
 import PocketBase from 'pocketbase'
 
-const pbUrl = import.meta.env.VITE_PB_URL || '/api'
+const pbUrl = import.meta.env.VITE_PB_URL || 'http://localhost:8090'
 
 export const pb = new PocketBase(pbUrl)