chore(restructure): reorganize project layout

- Reorganize internal packages and overall project structure
- Update imports and wiring to match the new layout
- Separate HTTP parsing and streaming from the server package
- Separate middleware from the server package
- Separate session registry from the session package
- Move HTTP, HTTPS, and TCP servers to the transport package
- Session package no longer starts the TCP server directly
- Server package no longer starts HTTP/HTTPS servers on initialization
- Forwarder no longer handles accepting TCP requests
- Move session details to the types package
- HTTP/HTTPS initialization is now the responsibility of main

internal/middleware/forwardedfor.go

@@ -0,0 +1,23 @@
+package middleware
+
+import (
+	"net"
+	"tunnel_pls/internal/http/header"
+)
+
+type ForwardedFor struct {
+	addr net.Addr
+}
+
+func NewForwardedFor(addr net.Addr) *ForwardedFor {
+	return &ForwardedFor{addr: addr}
+}
+
+func (ff *ForwardedFor) HandleRequest(header header.RequestHeader) error {
+	host, _, err := net.SplitHostPort(ff.addr.String())
+	if err != nil {
+		return err
+	}
+	header.Set("X-Forwarded-For", host)
+	return nil
+}