Fix web UI messaging, alias resolution, and onboarding

Messaging:
- Append \n to WS IPC sends so bufio.Scanner fires (messages from web
  were silently dropped — the line scanner never saw a newline)
- Handle session_ready in web store to update peer aliases after hello

Alias resolution:
- Seed AddPeer alias from SQLite cache so returning peers resolve
  immediately, before hello exchange completes
- Remove stale SavePeer call from AddPeer (was writing placeholder IDs)
- Add PeerAlias() point-lookup to store

Onboarding redesign:
- Three-state UI: disconnected (daemon instructions), connecting,
  connected-no-network (join form)
- Read ?n= / ?network= / ?anchor= / ?invite=waste:... URL params to
  pre-fill the join form for invite links
- Show daemon alias + peer ID before any network is joined
  (master_alias + master_id now included in state_snapshot)
- Identity backup: export (passphrase-protected yaw-key-backup-1 JSON,
  download button) and restore (paste + passphrase verify)

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

web/src/store/index.ts

@@ -8,6 +8,8 @@ interface WasteState {
   daemonStatus: 'disconnected' | 'connecting' | 'connected'
 
   // identity
+  masterAlias: string | null
+  masterId: string | null
   localPeer: PeerInfo | null
 
   // networks
@@ -24,6 +26,9 @@ interface WasteState {
   // file listings — keyed by peer id
   fileLists: Record<string, FileEntry[]>
 
+  // identity backup export result (cleared when consumed)
+  exportedBackup: string | null
+
   // actions
   connect: (url: string) => void
   disconnect: () => void
@@ -36,6 +41,8 @@ interface WasteState {
 export const useWaste = create<WasteState>((set, get) => ({
   adapter: null,
   daemonStatus: 'disconnected',
+  masterAlias: null,
+  masterId: null,
   localPeer: null,
   networks: [],
   activeNetworkId: null,
@@ -43,6 +50,7 @@ export const useWaste = create<WasteState>((set, get) => ({
   messages: {},
   activeRoom: 'general',
   fileLists: {},
+  exportedBackup: null,
 
   connect(url: string) {
     const adapter = new DaemonAdapter(url)
@@ -74,6 +82,8 @@ export const useWaste = create<WasteState>((set, get) => ({
       case 'state_snapshot': {
         const networks = msg.networks ?? []
         set({
+          masterAlias: msg.master_alias ?? null,
+          masterId: msg.master_id ?? null,
           localPeer: msg.local_peer ?? null,
           networks,
           connectedPeers: msg.connected_peers ?? [],
@@ -113,6 +123,16 @@ export const useWaste = create<WasteState>((set, get) => ({
         }
         break
       }
+      case 'session_ready': {
+        if (msg.peer_id && msg.nick) {
+          set(s => ({
+            connectedPeers: s.connectedPeers.map(p =>
+              p.id === msg.peer_id ? { ...p, alias: msg.nick! } : p
+            ),
+          }))
+        }
+        break
+      }
       case 'peer_disconnected': {
         set(s => ({
           connectedPeers: s.connectedPeers.filter(p => p.id !== msg.peer_id),
@@ -121,16 +141,20 @@ export const useWaste = create<WasteState>((set, get) => ({
       }
       case 'message_received': {
         if (msg.message) {
-          const room = msg.message.room
-          set(s => ({
-            messages: {
-              ...s.messages,
-              [room]: [...(s.messages[room] ?? []), msg.message!],
-            },
-          }))
+          const m = msg.message
+          const room = m.room
+          set(s => {
+            const existing = s.messages[room] ?? []
+            if (m.mid && existing.some(e => e.mid === m.mid)) return s
+            return { messages: { ...s.messages, [room]: [...existing, m] } }
+          })
         }
         break
       }
+      case 'identity_exported': {
+        if (msg.backup) set({ exportedBackup: msg.backup })
+        break
+      }
       case 'file_list': {
         if (msg.peer_id && msg.files) {
           set(s => ({