feat: --mode local 一键本地模式 (SQLite + redka, 无需 MySQL/Redis)

- main.go: --mode local 自动配置 db-driver=sqlite, db-name=data/sqlite3.db, redis-driver=redka
- database: 切换纯 Go SQLite 驱动 (github.com/glebarez/sqlite) — 无需 CGO
- docker-compose.yml: backend 添加 MODE=${MODE:-release} env var + data 卷挂载
- run.sh: binary upgrade 默认 --mode local, config.yaml 模板更新为 local 模式
- K8s quick-deploy.yaml: 单容器部署, MODE=local 环境变量切换远程/本地

backend/pkg/database/database.go

@@ -9,7 +9,7 @@ import (
 
 	"gorm.io/driver/mysql"
 	"gorm.io/driver/postgres"
-	"gorm.io/driver/sqlite"
+	"github.com/glebarez/sqlite"
 	"gorm.io/gorm"
 	"gorm.io/gorm/logger"
 )