feat(chat): implement sequence pre-allocation, versioned sync, and push worker

Introduce several performance and synchronization enhancements:
- Implement `SeqBufferManager` to allow sequence number pre-allocation via Redis Lua scripts, reducing atomic increment overhead.
- Add `PushWorker` to handle asynchronous message pushing using Redis Streams.
- Implement incremental conversation synchronization via `ConversationVersionLog` to allow clients to fetch only recent changes.
- Add support for Gzip compression in WebSocket communications to reduce bandwidth usage.
- Update dependency injection and configuration to support these new components.

internal/pkg/ws/compress.go

@@ -0,0 +1,71 @@
+package ws
+
+import (
+	"bytes"
+	"compress/gzip"
+	"io"
+	"sync"
+)
+
+const gzipMagicByte = 0x1F
+
+// Compressor 管理 gzip Writer/Reader 的 sync.Pool 复用
+type Compressor struct {
+	writerPool sync.Pool
+	readerPool sync.Pool
+	level      int
+}
+
+// NewCompressor 创建 Compressor（level: gzip.DefaultCompression/BestSpeed/BestCompression 等）
+func NewCompressor(level int) *Compressor {
+	return &Compressor{
+		level: level,
+		writerPool: sync.Pool{
+			New: func() any {
+				w, _ := gzip.NewWriterLevel(io.Discard, level)
+				return w
+			},
+		},
+		readerPool: sync.Pool{
+			New: func() any { return new(gzip.Reader) },
+		},
+	}
+}
+
+// Compress 压缩数据，返回 gzip 字节
+func (c *Compressor) Compress(data []byte) ([]byte, error) {
+	buf := &bytes.Buffer{}
+	w := c.writerPool.Get().(*gzip.Writer)
+	w.Reset(buf)
+	if _, err := w.Write(data); err != nil {
+		c.writerPool.Put(w)
+		return nil, err
+	}
+	if err := w.Close(); err != nil {
+		c.writerPool.Put(w)
+		return nil, err
+	}
+	c.writerPool.Put(w)
+	return buf.Bytes(), nil
+}
+
+// Decompress 解压 gzip 数据
+func (c *Compressor) Decompress(data []byte) ([]byte, error) {
+	r := c.readerPool.Get().(*gzip.Reader)
+	if err := r.Reset(bytes.NewReader(data)); err != nil {
+		c.readerPool.Put(r)
+		return nil, err
+	}
+	out, err := io.ReadAll(r)
+	r.Close()
+	c.readerPool.Put(r)
+	return out, err
+}
+
+// IsCompressed 检查数据是否以 gzip magic byte 开头
+func IsCompressed(data []byte) bool {
+	return len(data) > 0 && data[0] == gzipMagicByte
+}
+
+// DefaultCompressor 全局默认压缩器（gzip.DefaultCompression = level 6）
+var DefaultCompressor = NewCompressor(gzip.DefaultCompression)