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/App.css

@@ -20,11 +20,31 @@ input { background: var(--surface); color: var(--text); border: 1px solid var(--
 input:focus { border-color: var(--accent); }
 
 /* ── onboarding ── */
-.onboarding { display: flex; flex-direction: column; align-items: center; justify-content: center; height: 100%; gap: 16px; }
-.onboarding h1 { font-size: 2rem; letter-spacing: 0.1em; color: var(--accent); }
-.onboarding .status { color: var(--muted); }
-.join-form { display: flex; gap: 8px; }
-.join-form input { width: 220px; }
+.onboarding { display: flex; flex-direction: column; align-items: center; justify-content: center; height: 100%; gap: 12px; max-width: 380px; margin: 0 auto; padding: 2rem; }
+.onboarding h1 { font-size: 2rem; letter-spacing: 0.1em; color: var(--accent); margin-bottom: 4px; }
+.onboarding .status { color: var(--muted); font-size: 13px; }
+.onboarding .status.connecting { color: var(--accent); }
+.onboarding .status.disconnected { color: #e06060; }
+.onboarding-identity { text-align: center; }
+.onboarding-identity .alias { display: block; font-size: 1.1rem; font-weight: 600; }
+.onboarding-identity .peer-id { display: block; color: var(--muted); font-size: 11px; margin-top: 2px; }
+.onboarding-hint { color: var(--muted); font-size: 12px; text-align: center; }
+.onboarding-hint.muted { color: var(--muted); }
+.onboarding-code { background: var(--surface); border: 1px solid var(--border); border-radius: 4px; padding: 8px 12px; font-size: 12px; font-family: monospace; color: var(--text); width: 100%; text-align: left; }
+.onboarding-section { width: 100%; border-top: 1px solid var(--border); padding-top: 12px; }
+.join-form { display: flex; flex-direction: column; gap: 8px; width: 100%; }
+.join-form input { width: 100%; }
+.join-label { font-size: 11px; text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); }
+button.primary { background: var(--accent); width: 100%; padding: 8px; font-size: 14px; }
+.toggle-link { background: none; color: var(--muted); font-size: 12px; padding: 4px 0; text-align: left; }
+.toggle-link:hover { color: var(--text); }
+.backup-panel { display: flex; flex-direction: column; gap: 8px; margin-top: 8px; }
+.backup-form { display: flex; flex-direction: column; gap: 6px; }
+.backup-form textarea { background: var(--surface); color: var(--text); border: 1px solid var(--border); border-radius: 4px; padding: 6px 8px; font-size: 11px; resize: vertical; }
+.export-result { display: flex; flex-direction: column; gap: 6px; }
+.export-result textarea { font-size: 10px; }
+.mono { font-family: monospace; }
+details summary { color: var(--muted); font-size: 12px; cursor: pointer; }
 
 /* ── chat layout ── */
 .chat-layout { display: grid; grid-template-columns: var(--sidebar-w) 1fr var(--peerlist-w); height: 100%; }