feat(client): Add bandwidth limit function support

- Implement client bandwidth limitation parameter --bandwidth, supporting 1M, 1MB, 1G and other formats
- Added parseBandwidth function to parse bandwidth values and verify them
- Added bandwidth limit option in HTTP, HTTPS, TCP commands
- Pass bandwidth configuration to the server through protocol
- Add relevant test cases to verify the bandwidth analysis function

feat(server): implements server-side bandwidth limitation function

- Add bandwidth limitation logic in connection processing, using token bucket algorithm
- Implement an effective rate limiting strategy that minimizes the bandwidth of the client and server
- Added QoS limiter and restricted connection wrapper
- Integrated bandwidth throttling in HTTP and WebSocket proxies
- Added global bandwidth limit and burst multiplier settings in server configuration

docs: Updated documentation to describe bandwidth limiting functionality

- Add 2025-02-14 version update instructions in README and README_CN
- Add bandwidth limit function description and usage examples
- Provide client and server configuration examples and parameter descriptions

internal/server/proxy/handler.go

@@ -20,6 +20,7 @@ import (
 	"drip/internal/shared/netutil"
 	"drip/internal/shared/pool"
 	"drip/internal/shared/protocol"
+	"drip/internal/shared/qos"
 )
 
 // bufio.Reader pool to reduce allocations on hot path
@@ -247,7 +248,14 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	tconn.IncActiveConnections()
 	defer tconn.DecActiveConnections()
 
-	countingStream := netutil.NewCountingConn(stream,
+	var limitedStream net.Conn = stream
+	if limiter := tconn.GetLimiter(); limiter != nil && limiter.IsLimited() {
+		if l, ok := limiter.(*qos.Limiter); ok {
+			limitedStream = qos.NewLimitedConn(r.Context(), stream, l)
+		}
+	}
+
+	countingStream := netutil.NewCountingConn(limitedStream,
 		tconn.AddBytesOut,
 		tconn.AddBytesIn,
 	)