feat: implement Redis Streams support with stream checkpoints and update history

- Added Redis Streams operations to the message bus interface and implementation.
- Introduced StreamCheckpoint model to track last processed stream entry per document.
- Implemented UpsertStreamCheckpoint and GetStreamCheckpoint methods in the Postgres store.
- Created document_update_history table for storing update payloads for recovery and replay.
- Developed update persist worker to handle Redis Stream updates and persist them to Postgres.
- Enhanced Docker Compose configuration for Redis with persistence.
- Updated frontend API to support fetching document state with optional share token.
- Added connection stability monitoring in the Yjs document hook.

backend/internal/logger/logger.go

@@ -23,7 +23,7 @@ func NewLogger(isDevelopment bool) (*zap.Logger, error) {
     // 👇 关键修改：直接拉到 Fatal 级别
     // 这样 Error, Warn, Info, Debug 全部都会被忽略
     // 彻底消除 IO 锁竞争
-    config.Level = zap.NewAtomicLevelAt(zapcore.FatalLevel)
+    config.Level = zap.NewAtomicLevelAt(zapcore.InfoLevel)
 
     logger, err := config.Build()
     if err != nil {