feat(pcap): complete replay system with filtering, metadata, and live replay

Wire ExcludeOpcodes config into RecordingConn so configured opcodes
(e.g. ping, nop, position) are filtered at record time. Add padded
metadata with in-place PatchMetadata to populate CharID/UserID after
login. Implement --mode replay using protbot's encrypted connection
with timing-aware packet sending, auto-ping response, concurrent
S→C collection, and byte-level payload diff reporting.

server/channelserver/sys_session.go

@@ -74,14 +74,15 @@ type Session struct {
 	Name           string
 	closed         atomic.Bool
 	ackStart       map[uint32]time.Time
-	captureCleanup func() // Called on session close to flush/close capture file
+	captureConn    *pcap.RecordingConn // non-nil when capture is active
+	captureCleanup func()              // Called on session close to flush/close capture file
 }
 
 // NewSession creates a new Session type.
 func NewSession(server *Server, conn net.Conn) *Session {
 	var cryptConn network.Conn = network.NewCryptConn(conn, server.erupeConfig.RealClientMode, server.logger.Named(conn.RemoteAddr().String()))
 
-	cryptConn, captureCleanup := startCapture(server, cryptConn, conn.RemoteAddr(), pcap.ServerTypeChannel)
+	cryptConn, captureConn, captureCleanup := startCapture(server, cryptConn, conn.RemoteAddr(), pcap.ServerTypeChannel)
 
 	s := &Session{
 		logger:         server.logger.Named(conn.RemoteAddr().String()),
@@ -96,6 +97,7 @@ func NewSession(server *Server, conn net.Conn) *Session {
 		stageMoveStack: stringstack.New(),
 		ackStart:       make(map[uint32]time.Time),
 		semaphoreID:    make([]uint16, 2),
+		captureConn:    captureConn,
 		captureCleanup: captureCleanup,
 	}
 	return s