Add invite strings (waste: URI) for peer onboarding

- internal/invite: Encode/Decode waste:<base64json{anchor,network}>
- proto: CmdGenerateInvite + EvtInviteGenerated + InviteString field
- ipc: track active network name; handle generate_invite (returns invite
  string when joined to a network, errors if not joined or no anchor)
- daemon: --join <invite> flag — decodes anchor URL + network name,
  sets anchor and auto-joins on startup
- tui: --join <invite> flag — extracts network name, skips -network
  requirement; ctrl+i generates invite and shows it full-screen;
  Esc dismisses the invite overlay
- FUTURE.md: document multi-network derived-identity design

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

FUTURE.md

@@ -59,6 +59,33 @@ No DHT needed at small group scale (10–50 nodes). Keep it simple:
 - Public key = stable identity, not a mutable nickname
 - No phone number, no central registry — closer to Signal's model than WASTE's original unregistered aliases
 
+### Multi-Network Support
+
+A single client should be able to participate in multiple networks simultaneously (e.g. "work" and "friends") without leaking that both identities belong to the same person.
+
+**Privacy constraint:** if the same Ed25519 keypair is used across networks, any peer who is a member of both networks can trivially correlate you. The anchor also sees the same public key across networks.
+
+**Solution — per-network derived identities:**
+- One master Ed25519 seed in `identity.json`
+- Per-network keypair = `HKDF(masterSeed, "yaw2-net", networkHash)`
+- Same master + same network name = same derived keypair (stable identity within a network)
+- Different networks = different peer IDs; correlation is impossible without knowing both network names
+- The anchor sees only the derived public key
+
+**Daemon changes:**
+- Replace the single `networkCancel` with a `map[networkID]*networkCtx`
+- Each context holds its own: derived identity, mesh, anchor connection, store (`messages-<netHash>.db`)
+- `join_network` returns a `network_id` token used to scope subsequent commands
+
+**IPC changes (breaking):**
+- All commands and events gain a `network_id` field
+- `get_state` returns an array of all joined networks
+- `join_network` responds with `network_joined` carrying the derived peer ID for that network
+
+**TUI changes:**
+- Top-level network switcher (e.g. `[work] [friends]`)
+- Rooms and peers are scoped per network underneath
+
 ### Transport (Long-term)
 Current transport is TCP with custom framing. QUIC is worth revisiting once the core is solid — it gives multiplexing and better NAT traversal behavior essentially for free.
 

cmd/daemon/main.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/waste-go/internal/anchor"
 	"github.com/waste-go/internal/crypto"
+	"github.com/waste-go/internal/invite"
 	"github.com/waste-go/internal/ipc"
 	"github.com/waste-go/internal/mesh"
 	"github.com/waste-go/internal/proto"
@@ -22,8 +23,21 @@ func main() {
 	alias     := flag.String("alias", "anon", "display name shown to peers (advisory only)")
 	ipcPort   := flag.Int("ipc-port", 17337, "port for local IPC (UI connects here)")
 	anchorURL := flag.String("anchor", "", "anchor WebSocket URL, e.g. ws://your-vps:17339/ws")
+	joinInvite := flag.String("join", "", "waste: invite string — sets anchor URL and auto-joins the network on startup")
 	flag.Parse()
 
+	// --join overrides/sets the anchor URL and triggers an auto-join.
+	var autoJoinNetwork string
+	if *joinInvite != "" {
+		inv, err := invite.Decode(*joinInvite)
+		if err != nil {
+			log.Fatalf("invalid invite: %v", err)
+		}
+		*anchorURL = inv.Anchor
+		autoJoinNetwork = inv.Network
+		log.Printf("daemon: invite decoded — anchor=%s network=%s", inv.Anchor, inv.Network)
+	}
+
 	dir := expandHome(*dataDir)
 	id, err := crypto.LoadOrCreate(dir, *alias)
 	if err != nil {
@@ -51,7 +65,14 @@ func main() {
 		log.Printf("daemon: left network %q", networkName)
 	}
 
-	if err := ipc.Run(m, *ipcPort, joinFn); err != nil {
+	// Auto-join from --join flag before starting IPC (non-blocking).
+	if autoJoinNetwork != "" {
+		ctx, cancel := context.WithCancel(context.Background())
+		_ = cancel // lifecycle managed by the joinFn / ipc.Run leave
+		go joinFn(ctx, autoJoinNetwork)
+	}
+
+	if err := ipc.Run(m, *ipcPort, *anchorURL, joinFn); err != nil {
 		log.Fatalf("ipc: %v", err)
 	}
 }

cmd/tui/main.go

@@ -18,6 +18,7 @@ import (
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
 
+	"github.com/waste-go/internal/invite"
 	"github.com/waste-go/internal/proto"
 )
 
@@ -116,6 +117,7 @@ type model struct {
 
 	status      string
 	errMsg      string
+	invitePopup string // non-empty = show invite overlay
 }
 
 func newModel(ipcPort int, network string) model {
@@ -200,7 +202,15 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		case msg.Type == tea.KeyCtrlC:
 			return m, tea.Quit
 		case msg.Type == tea.KeyEsc:
+			if m.invitePopup != "" {
+				m.invitePopup = ""
+				return m, nil
+			}
 			return m, tea.Quit
+		case msg.String() == "ctrl+i":
+			if m.enc != nil {
+				cmds = append(cmds, sendIPC(m.enc, proto.IpcMessage{Type: proto.CmdGenerateInvite}))
+			}
 		case msg.Type == tea.KeyEnter:
 			m, cmds = m.doSend(cmds)
 		case msg.Type == tea.KeyTab:
@@ -272,6 +282,9 @@ func (m model) applyEvent(evt proto.IpcMessage) model {
 			m.peerOrder = filterIDs(m.peerOrder, pid)
 		}
 
+	case proto.EvtInviteGenerated:
+		m.invitePopup = evt.InviteString
+
 	case proto.EvtMessageReceived:
 		if evt.Message != nil {
 			msg := evt.Message
@@ -417,11 +430,31 @@ func (m model) View() string {
 	if m.errMsg != "" {
 		statusLine = styleErr.Render(" ✗ " + m.errMsg)
 	} else {
-		hint := "  tab: rooms · pgup/dn: scroll · ctrl+c: quit"
+		hint := "  tab: rooms · ctrl+i: invite · ctrl+c: quit"
 		statusLine = styleStatus.Width(m.width).Render(" " + m.status + hint)
 	}
 
-	return lipgloss.JoinVertical(lipgloss.Left, mainRow, inputBox, statusLine)
+	view := lipgloss.JoinVertical(lipgloss.Left, mainRow, inputBox, statusLine)
+
+	// ── invite popup (full-screen overlay) ───────────────────────────────────
+	if m.invitePopup != "" {
+		label := styleActive.Render("Invite — share this with anyone you want to add:")
+		code := lipgloss.NewStyle().
+			Border(lipgloss.RoundedBorder()).
+			BorderForeground(lipgloss.Color("238")).
+			Padding(0, 1).
+			Width(m.width - 6).
+			Render(m.invitePopup)
+		hint := styleStatus.Render("Esc to close  ·  ctrl+c to quit")
+		popup := lipgloss.NewStyle().
+			Width(m.width).
+			Height(m.height).
+			Align(lipgloss.Center, lipgloss.Center).
+			Render(lipgloss.JoinVertical(lipgloss.Left, label, "", code, "", hint))
+		return popup
+	}
+
+	return view
 }
 
 func (m model) renderRooms(boxH int) string {
@@ -566,11 +599,22 @@ func min(a, b int) int {
 
 func main() {
 	ipcPort     := flag.Int("ipc", 17337, "daemon IPC port")
-	network := flag.String("network", "", "network name to join on startup (required)")
+	network     := flag.String("network", "", "network name to join on startup")
+	joinInvite  := flag.String("join", "", "waste: invite string — auto-sets the network name")
 	flag.Parse()
 
+	// --join overrides --network.
+	if *joinInvite != "" {
+		inv, err := invite.Decode(*joinInvite)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "error: invalid invite:", err)
+			os.Exit(1)
+		}
+		*network = inv.Network
+	}
+
 	if *network == "" {
-		fmt.Fprintln(os.Stderr, "error: -network is required")
+		fmt.Fprintln(os.Stderr, "error: -network or -join is required")
 		flag.Usage()
 		os.Exit(1)
 	}

internal/invite/invite.go

@@ -0,0 +1,54 @@
+// Package invite encodes and decodes waste invite strings.
+// An invite carries the anchor URL and network name needed to join a network.
+// Format: "waste:<url-safe-base64(json)>"
+package invite
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"strings"
+)
+
+const prefix = "waste:"
+
+// Invite holds the information needed to join a network.
+type Invite struct {
+	Anchor  string `json:"anchor"`  // WebSocket anchor URL
+	Network string `json:"network"` // plaintext network name
+}
+
+// Encode returns a waste: invite string for the given anchor URL and network name.
+func Encode(anchor, network string) (string, error) {
+	if anchor == "" {
+		return "", fmt.Errorf("anchor URL is required")
+	}
+	if network == "" {
+		return "", fmt.Errorf("network name is required")
+	}
+	b, err := json.Marshal(Invite{Anchor: anchor, Network: network})
+	if err != nil {
+		return "", err
+	}
+	return prefix + base64.URLEncoding.EncodeToString(b), nil
+}
+
+// Decode parses a waste: invite string and returns the Invite.
+func Decode(s string) (Invite, error) {
+	s = strings.TrimSpace(s)
+	if !strings.HasPrefix(s, prefix) {
+		return Invite{}, fmt.Errorf("not a waste invite (expected 'waste:' prefix)")
+	}
+	b, err := base64.URLEncoding.DecodeString(strings.TrimPrefix(s, prefix))
+	if err != nil {
+		return Invite{}, fmt.Errorf("invalid invite: %w", err)
+	}
+	var inv Invite
+	if err := json.Unmarshal(b, &inv); err != nil {
+		return Invite{}, fmt.Errorf("invalid invite payload: %w", err)
+	}
+	if inv.Anchor == "" || inv.Network == "" {
+		return Invite{}, fmt.Errorf("invite is missing anchor or network name")
+	}
+	return inv, nil
+}

internal/invite/invite_test.go

@@ -0,0 +1,38 @@
+package invite
+
+import "testing"
+
+func TestRoundTrip(t *testing.T) {
+	s, err := Encode("ws://my-vps:17339/ws", "friends")
+	if err != nil {
+		t.Fatalf("Encode: %v", err)
+	}
+	if len(s) < 7 || s[:6] != "waste:" {
+		t.Fatalf("expected waste: prefix, got %q", s)
+	}
+
+	inv, err := Decode(s)
+	if err != nil {
+		t.Fatalf("Decode: %v", err)
+	}
+	if inv.Anchor != "ws://my-vps:17339/ws" {
+		t.Fatalf("anchor = %q", inv.Anchor)
+	}
+	if inv.Network != "friends" {
+		t.Fatalf("network = %q", inv.Network)
+	}
+}
+
+func TestDecodeInvalid(t *testing.T) {
+	cases := []string{
+		"",
+		"notaninvite",
+		"waste:!!!",
+		"waste:" + "eyJhbmNob3IiOiIifQ==", // missing network
+	}
+	for _, c := range cases {
+		if _, err := Decode(c); err == nil {
+			t.Errorf("Decode(%q) expected error, got nil", c)
+		}
+	}
+}

internal/ipc/ipc.go

@@ -16,6 +16,7 @@ import (
 	"time"
 
 	"github.com/google/uuid"
+	"github.com/waste-go/internal/invite"
 	"github.com/waste-go/internal/mesh"
 	"github.com/waste-go/internal/proto"
 )
@@ -24,8 +25,9 @@ import (
 type JoinFunc func(ctx context.Context, networkName string)
 
 // Run starts the IPC listener. Blocks until the listener fails.
+// anchorURL is the configured anchor WebSocket URL (used for invite generation).
 // Network join/leave state is daemon-scoped (shared across all IPC clients).
-func Run(m *mesh.Mesh, port int, join JoinFunc) error {
+func Run(m *mesh.Mesh, port int, anchorURL string, join JoinFunc) error {
 	addr := fmt.Sprintf("127.0.0.1:%d", port)
 	ln, err := net.Listen("tcp", addr)
 	if err != nil {
@@ -33,11 +35,12 @@ func Run(m *mesh.Mesh, port int, join JoinFunc) error {
 	}
 	log.Printf("ipc: listening on %s", addr)
 
-	// networkCancel is shared across all clients — any client can join/leave,
+	// networkCancel / networkName are shared across all clients — any client
-	// and the join persists even after the commanding client disconnects.
+	// can join/leave, and the join persists after the commanding client disconnects.
 	var (
 		networkMu     sync.Mutex
 		networkCancel context.CancelFunc
+		networkName   string
 	)
 
 	doJoin := func(name string) {
@@ -47,6 +50,7 @@ func Run(m *mesh.Mesh, port int, join JoinFunc) error {
 		}
 		ctx, cancel := context.WithCancel(context.Background())
 		networkCancel = cancel
+		networkName = name
 		networkMu.Unlock()
 		go join(ctx, name)
 	}
@@ -56,21 +60,28 @@ func Run(m *mesh.Mesh, port int, join JoinFunc) error {
 		if networkCancel != nil {
 			networkCancel()
 			networkCancel = nil
+			networkName = ""
 		}
 		networkMu.Unlock()
 	}
 
+	currentNetwork := func() string {
+		networkMu.Lock()
+		defer networkMu.Unlock()
+		return networkName
+	}
+
 	for {
 		conn, err := ln.Accept()
 		if err != nil {
 			return fmt.Errorf("ipc accept: %w", err)
 		}
 		log.Printf("ipc: UI client connected from %s", conn.RemoteAddr())
-		go handleClient(conn, m, doJoin, doLeave)
+		go handleClient(conn, m, anchorURL, currentNetwork, doJoin, doLeave)
 	}
 }
 
-func handleClient(conn net.Conn, m *mesh.Mesh, doJoin func(string), doLeave func()) {
+func handleClient(conn net.Conn, m *mesh.Mesh, anchorURL string, currentNetwork func() string, doJoin func(string), doLeave func()) {
 	defer conn.Close()
 
 	events := m.Subscribe()
@@ -187,6 +198,23 @@ func handleClient(conn net.Conn, m *mesh.Mesh, doJoin func(string), doLeave func
 				Rooms:          []string{"general"},
 			})
 
+		case proto.CmdGenerateInvite:
+			net := currentNetwork()
+			if net == "" {
+				send(errMsg("generate_invite: not currently joined to a network"))
+				continue
+			}
+			if anchorURL == "" {
+				send(errMsg("generate_invite: daemon was started without -anchor flag"))
+				continue
+			}
+			inv, err := invite.Encode(anchorURL, net)
+			if err != nil {
+				send(errMsg(fmt.Sprintf("generate_invite: %v", err)))
+				continue
+			}
+			send(proto.IpcMessage{Type: proto.EvtInviteGenerated, InviteString: inv})
+
 		case proto.CmdSendFile:
 			send(errMsg("file transfer not yet implemented"))
 

internal/proto/proto.go

@@ -186,6 +186,7 @@ const (
 	CmdLeaveNetwork IpcMsgType = "leave_network"
 	CmdGetState     IpcMsgType = "get_state"
 	CmdSendFile      IpcMsgType = "send_file"
+	CmdGenerateInvite IpcMsgType = "generate_invite"
 
 	// Events (daemon → UI)
 	EvtMessageReceived  IpcMsgType = "message_received"
@@ -196,6 +197,7 @@ const (
 	EvtFileProgress     IpcMsgType = "file_progress"
 	EvtStateSnapshot    IpcMsgType = "state_snapshot"
 	EvtError            IpcMsgType = "error"
+	EvtInviteGenerated  IpcMsgType = "invite_generated"
 )
 
 // IpcMessage covers both commands and events.
@@ -226,4 +228,5 @@ type IpcMessage struct {
 	ConnectedPeers []PeerInfo   `json:"connected_peers,omitempty"`
 	Rooms          []string     `json:"rooms,omitempty"`
 	ErrorMessage   string       `json:"error_message,omitempty"`
+	InviteString   string       `json:"invite,omitempty"`
 }