feat(api-key): add independent quota and expiration support

This feature allows API Keys to have their own quota limits and expiration
times, independent of the user's balance.

Backend:
- Add quota, quota_used, expires_at fields to api_key schema
- Implement IsExpired() and IsQuotaExhausted() checks in middleware
- Add ResetQuota and ClearExpiration API endpoints
- Integrate quota billing in gateway handlers (OpenAI, Anthropic, Gemini)
- Include quota/expiration fields in auth cache for performance
- Expiration check returns 403, quota exhausted returns 429

Frontend:
- Add quota and expiration inputs to key create/edit dialog
- Add quick-select buttons for expiration (+7, +30, +90 days)
- Add reset quota confirmation dialog
- Add expires_at column to keys list
- Add i18n translations for new features (en/zh)

Migration:
- Add 045_add_api_key_quota.sql for new columns

backend/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.25.5-alpine
+FROM golang:1.25.6-alpine
 
 WORKDIR /app
 
@@ -15,7 +15,7 @@ RUN go mod download
 COPY . .
 
 # 构建应用
-RUN go build -o main cmd/server/main.go
+RUN go build -o main ./cmd/server/
 
 # 暴露端口
 EXPOSE 8080