⭐ feat: Migrate from WebSocket to libp2p for peer-to-peer connectivity (#286)

## Description
Whew, some stuff is still not re-implemented, but it's working!

Rabbit's gonna explode with the amount of changes I reckon 😅



<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Introduced a peer-to-peer relay system using libp2p with enhanced
stream forwarding, room state synchronization, and mDNS peer discovery.
- Added decentralized room and participant management, metrics
publishing, and safe, size-limited, concurrent message streaming with
robust framing and callback dispatching.
- Implemented asynchronous, callback-driven message handling over custom
libp2p streams replacing WebSocket signaling.
- **Improvements**
- Migrated signaling and stream protocols from WebSocket to libp2p,
improving reliability and scalability.
- Simplified configuration and environment variables, removing
deprecated flags and adding persistent data support.
- Enhanced logging, error handling, and connection management for better
observability and robustness.
- Refined RTP header extension registration and NAT IP handling for
improved WebRTC performance.
- **Bug Fixes**
- Improved ICE candidate buffering and SDP negotiation in WebRTC
connections.
  - Fixed NAT IP and UDP port range configuration issues.
- **Refactor**
- Modularized codebase, reorganized relay and server logic, and removed
deprecated WebSocket-based components.
- Streamlined message structures, removed obsolete enums and message
types, and simplified SafeMap concurrency.
- Replaced WebSocket signaling with libp2p stream protocols in server
and relay components.
- **Chores**
- Updated and cleaned dependencies across Go, Rust, and JavaScript
packages.
  - Added `.gitignore` for persistent data directory in relay package.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: DatCaptainHorse <DatCaptainHorse@users.noreply.github.com>
Co-authored-by: Philipp Neumann <3daquawolf@gmail.com>

packages/relay/internal/common/flags.go

@@ -2,47 +2,43 @@ package common
 
 import (
 	"flag"
-	"github.com/pion/webrtc/v4"
 	"log/slog"
 	"net"
 	"os"
 	"strconv"
-	"strings"
+
+	"github.com/pion/webrtc/v4"
 )
 
 var globalFlags *Flags
 
 type Flags struct {
-	Verbose        bool     // Log everything to console
-	Debug          bool     // Enable debug mode, implies Verbose
-	EndpointPort   int      // Port for HTTP/S and WS/S endpoint (TCP)
-	MeshPort       int      // Port for Mesh connections (TCP)
-	WebRTCUDPStart int      // WebRTC UDP port range start - ignored if UDPMuxPort is set
-	WebRTCUDPEnd   int      // WebRTC UDP port range end - ignored if UDPMuxPort is set
-	STUNServer     string   // WebRTC STUN server
-	UDPMuxPort     int      // WebRTC UDP mux port - if set, overrides UDP port range
-	AutoAddLocalIP bool     // Automatically add local IP to NAT 1 to 1 IPs
-	NAT11IPs       []string // WebRTC NAT 1 to 1 IP(s) - allows specifying host IP(s) if behind NAT
-	TLSCert        string   // Path to TLS certificate
-	TLSKey         string   // Path to TLS key
-	ControlSecret  string   // Shared secret for this relay's control endpoint
+	RegenIdentity  bool   // Remove old identity on startup and regenerate it
+	Verbose        bool   // Log everything to console
+	Debug          bool   // Enable debug mode, implies Verbose
+	EndpointPort   int    // Port for HTTP/S and WS/S endpoint (TCP)
+	WebRTCUDPStart int    // WebRTC UDP port range start - ignored if UDPMuxPort is set
+	WebRTCUDPEnd   int    // WebRTC UDP port range end - ignored if UDPMuxPort is set
+	STUNServer     string // WebRTC STUN server
+	UDPMuxPort     int    // WebRTC UDP mux port - if set, overrides UDP port range
+	AutoAddLocalIP bool   // Automatically add local IP to NAT 1 to 1 IPs
+	NAT11IP        string // WebRTC NAT 1 to 1 IP - allows specifying IP of relay if behind NAT
+	PersistDir     string // Directory to save persistent data to
 }
 
 func (flags *Flags) DebugLog() {
-	slog.Info("Relay flags",
+	slog.Debug("Relay flags",
+		"regenIdentity", flags.RegenIdentity,
 		"verbose", flags.Verbose,
 		"debug", flags.Debug,
 		"endpointPort", flags.EndpointPort,
-		"meshPort", flags.MeshPort,
 		"webrtcUDPStart", flags.WebRTCUDPStart,
 		"webrtcUDPEnd", flags.WebRTCUDPEnd,
 		"stunServer", flags.STUNServer,
 		"webrtcUDPMux", flags.UDPMuxPort,
 		"autoAddLocalIP", flags.AutoAddLocalIP,
-		"webrtcNAT11IPs", strings.Join(flags.NAT11IPs, ","),
-		"tlsCert", flags.TLSCert,
-		"tlsKey", flags.TLSKey,
-		"controlSecret", flags.ControlSecret,
+		"webrtcNAT11IPs", flags.NAT11IP,
+		"persistDir", flags.PersistDir,
 	)
 }
 
@@ -76,29 +72,25 @@ func InitFlags() {
 	// Create Flags struct
 	globalFlags = &Flags{}
 	// Get flags
+	flag.BoolVar(&globalFlags.RegenIdentity, "regenIdentity", getEnvAsBool("REGEN_IDENTITY", false), "Regenerate identity on startup")
 	flag.BoolVar(&globalFlags.Verbose, "verbose", getEnvAsBool("VERBOSE", false), "Verbose mode")
 	flag.BoolVar(&globalFlags.Debug, "debug", getEnvAsBool("DEBUG", false), "Debug mode")
 	flag.IntVar(&globalFlags.EndpointPort, "endpointPort", getEnvAsInt("ENDPOINT_PORT", 8088), "HTTP endpoint port")
-	flag.IntVar(&globalFlags.MeshPort, "meshPort", getEnvAsInt("MESH_PORT", 8089), "Mesh connections TCP port")
-	flag.IntVar(&globalFlags.WebRTCUDPStart, "webrtcUDPStart", getEnvAsInt("WEBRTC_UDP_START", 10000), "WebRTC UDP port range start")
-	flag.IntVar(&globalFlags.WebRTCUDPEnd, "webrtcUDPEnd", getEnvAsInt("WEBRTC_UDP_END", 20000), "WebRTC UDP port range end")
+	flag.IntVar(&globalFlags.WebRTCUDPStart, "webrtcUDPStart", getEnvAsInt("WEBRTC_UDP_START", 0), "WebRTC UDP port range start")
+	flag.IntVar(&globalFlags.WebRTCUDPEnd, "webrtcUDPEnd", getEnvAsInt("WEBRTC_UDP_END", 0), "WebRTC UDP port range end")
 	flag.StringVar(&globalFlags.STUNServer, "stunServer", getEnvAsString("STUN_SERVER", "stun.l.google.com:19302"), "WebRTC STUN server")
 	flag.IntVar(&globalFlags.UDPMuxPort, "webrtcUDPMux", getEnvAsInt("WEBRTC_UDP_MUX", 8088), "WebRTC UDP mux port")
 	flag.BoolVar(&globalFlags.AutoAddLocalIP, "autoAddLocalIP", getEnvAsBool("AUTO_ADD_LOCAL_IP", true), "Automatically add local IP to NAT 1 to 1 IPs")
 	// String with comma separated IPs
-	nat11IPs := ""
-	flag.StringVar(&nat11IPs, "webrtcNAT11IPs", getEnvAsString("WEBRTC_NAT_IPS", ""), "WebRTC NAT 1 to 1 IP(s), comma delimited")
-	flag.StringVar(&globalFlags.TLSCert, "tlsCert", getEnvAsString("TLS_CERT", ""), "Path to TLS certificate")
-	flag.StringVar(&globalFlags.TLSKey, "tlsKey", getEnvAsString("TLS_KEY", ""), "Path to TLS key")
-	flag.StringVar(&globalFlags.ControlSecret, "controlSecret", getEnvAsString("CONTROL_SECRET", ""), "Shared secret for control endpoint")
+	nat11IP := ""
+	flag.StringVar(&nat11IP, "webrtcNAT11IP", getEnvAsString("WEBRTC_NAT_IP", ""), "WebRTC NAT 1 to 1 IP")
+	flag.StringVar(&globalFlags.PersistDir, "persistDir", getEnvAsString("PERSIST_DIR", "./persist-data"), "Directory to save persistent data to")
 	// Parse flags
 	flag.Parse()
 
 	// If debug is enabled, verbose is also enabled
 	if globalFlags.Debug {
 		globalFlags.Verbose = true
-		// If Debug is enabled, set ControlSecret to 1234
-		globalFlags.ControlSecret = "1234"
 	}
 
 	// ICE STUN servers
@@ -108,24 +100,11 @@ func InitFlags() {
 		},
 	}
 
-	// Initialize NAT 1 to 1 IPs
-	globalFlags.NAT11IPs = []string{}
-
-	// Get local IP
-	if globalFlags.AutoAddLocalIP {
-		globalFlags.NAT11IPs = append(globalFlags.NAT11IPs, getLocalIP())
-	}
-
 	// Parse NAT 1 to 1 IPs from string
-	if len(nat11IPs) > 0 {
-		split := strings.Split(nat11IPs, ",")
-		if len(split) > 0 {
-			for _, ip := range split {
-				globalFlags.NAT11IPs = append(globalFlags.NAT11IPs, ip)
-			}
-		} else {
-			globalFlags.NAT11IPs = append(globalFlags.NAT11IPs, nat11IPs)
-		}
+	if len(nat11IP) > 0 {
+		globalFlags.NAT11IP = nat11IP
+	} else if globalFlags.AutoAddLocalIP {
+		globalFlags.NAT11IP = getLocalIP()
 	}
 }