feat: spaces redesign, model selector, auth fixes

Spaces:
- Perplexity-like UI with collaboration features
- Space detail page with threads/members tabs
- Invite members via email, role management
- New space creation with icon/color picker

Model selector:
- Added Ollama client for free Auto model
- GooSeek 1.0 via Timeweb (tariff-based)
- Frontend model dropdown in ChatInput

Auth & Infrastructure:
- Fixed auth-svc missing from Dockerfile.all
- Removed duplicate ratelimit_tiered.go (conflict)
- Added Redis to api-gateway for rate limiting
- Fixed Next.js proxy for local development

UI improvements:
- Redesigned login button in sidebar (gradient)
- Settings page with tabs (account/billing/prefs)
- Auth pages visual refresh

Made-with: Cursor

backend/webui/src/lib/auth.ts

@@ -7,6 +7,7 @@ export interface User {
   avatar?: string;
   role: 'user' | 'admin';
   tier: 'free' | 'pro' | 'business';
+  balance: number;
   emailVerified: boolean;
   provider: string;
   createdAt: string;