feat: auth service + security audit fixes + cleanup legacy services

Major changes:
- Add auth-svc: JWT auth, register/login/refresh, password reset
- Add auth UI: modals, pages (/login, /register, /forgot-password)
- Add usage tracking (usage_metrics table, daily limits)
- Add tiered rate limiting (free/pro/business)
- Add LLM usage limits per tier

Security fixes:
- All repos now require userID for Update/Delete operations
- JWT middleware in chat-svc, llm-svc, agent-svc, discover-svc
- ErrNotFound/ErrForbidden errors for proper access control

Cleanup:
- Remove legacy TypeScript services/ directory
- Remove computer-svc (to be reimplemented)
- Remove old deploy/docker configs

New files:
- backend/cmd/auth-svc/main.go
- backend/internal/auth/{types,repository}.go
- backend/internal/usage/{types,repository}.go
- backend/pkg/middleware/{llm_limits,ratelimit_tiered}.go
- backend/webui/src/components/auth/*
- backend/webui/src/app/(auth)/*

Made-with: Cursor

backend/go.mod

@@ -1,6 +1,8 @@
 module github.com/gooseek/backend
 
-go 1.22
+go 1.24
+
+toolchain go1.24.13
 
 require (
 	github.com/gofiber/fiber/v2 v2.52.0
@@ -11,7 +13,6 @@ require (
 	github.com/lib/pq v1.10.9
 	github.com/minio/minio-go/v7 v7.0.70
 	github.com/redis/go-redis/v9 v9.4.0
-	github.com/robfig/cron/v3 v3.0.1
 	github.com/sashabaranov/go-openai v1.20.0
 	go.uber.org/zap v1.27.0
 	golang.org/x/sync v0.6.0
@@ -29,8 +30,10 @@ require (
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mattn/go-runewidth v0.0.15 // indirect
 	github.com/minio/md5-simd v1.1.2 // indirect
+	github.com/philhofer/fwd v1.2.0 // indirect
 	github.com/rivo/uniseg v0.4.6 // indirect
 	github.com/rs/xid v1.5.0 // indirect
+	github.com/tinylib/msgp v1.6.3 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	github.com/valyala/fasthttp v1.52.0 // indirect
 	github.com/valyala/tcplisten v1.0.0 // indirect