feat: Phase 4 — off-grid Bitcoin relay, block headers, dead man's switch

- Typed message dispatch in listener (BlockHeader, TxRelay, LightningRelay, Alert, TxConfirmation)
- Base64 encoding for binary payloads over LoRa (fixes NUL byte truncation)
- Compact block header announcements (88 bytes, fits 160-byte LoRa limit)
- Block header announcer: internet nodes auto-announce new blocks to Archy peers
- TX relay: mesh-only nodes can broadcast transactions via internet-connected peers
- Confirmation tracking: relay node monitors 1/3, 2/3, 3/3 confirmations, sends updates back
- Dead man's switch background task with configurable interval and signed alert broadcast
- 6 new RPC endpoints: relay-tx, block-headers, relay-lightning, deadman-status/configure/checkin
- lnd.create-raw-tx: create signed TX without broadcasting (for mesh relay)
- Web5 wallet: offline detection + "Send via mesh?" prompt with auto relay + confirmation polling
- Mesh.vue: Off-Grid Bitcoin tab, Dead Man tab, Send Bitcoin/Lightning buttons
- TX/Lightning relay sends only to Archy peers (not broadcast to all devices)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

neode-ui/src/stores/mesh.ts

@@ -53,7 +53,8 @@ export interface MeshMessage {
   delivered: boolean
   encrypted: boolean
   message_type?: MeshMessageTypeLabel
-  typed_payload?: InvoiceData | AlertData | CoordinateData | null
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  typed_payload?: Record<string, any> | null
 }
 
 export interface InvoiceData {
@@ -94,6 +95,14 @@ export interface AlertStatus {
   emergency_contacts: number
 }
 
+export interface BlockHeader {
+  height: number
+  hash: string
+  prev_hash: string
+  timestamp: number
+  announced_by: string
+}
+
 export const useMeshStore = defineStore('mesh', () => {
   const status = ref<MeshStatus | null>(null)
   const peers = ref<MeshPeer[]>([])
@@ -269,8 +278,71 @@ export const useMeshStore = defineStore('mesh', () => {
     })
   }
 
+  // ─── Phase 4: Off-Grid Bitcoin Operations ────────────────────────────
+
+  const deadmanStatus = ref<AlertStatus | null>(null)
+  const blockHeaders = ref<BlockHeader[]>([])
+  const latestBlockHeight = ref(0)
+
+  async function fetchDeadmanStatus() {
+    try {
+      deadmanStatus.value = await rpcClient.call<AlertStatus>({ method: 'mesh.deadman-status' })
+    } catch {
+      // Dead man switch not available
+    }
+  }
+
+  async function configureDeadman(config: {
+    enabled?: boolean
+    interval_secs?: number
+    lat?: number
+    lng?: number
+    label?: string
+    contacts?: string[]
+    custom_message?: string
+    auto_gps?: boolean
+  }) {
+    return rpcClient.call<AlertStatus>({
+      method: 'mesh.deadman-configure',
+      params: config,
+    })
+  }
+
+  async function deadmanCheckin() {
+    return rpcClient.call<{ checked_in: boolean; time_remaining_secs: number }>({
+      method: 'mesh.deadman-checkin',
+    })
+  }
+
+  async function fetchBlockHeaders(count = 10) {
+    try {
+      const res = await rpcClient.call<{ headers: BlockHeader[]; latest_height: number; count: number }>({
+        method: 'mesh.block-headers',
+        params: { count },
+      })
+      blockHeaders.value = res.headers
+      latestBlockHeight.value = res.latest_height
+    } catch {
+      // Block headers not available
+    }
+  }
+
+  async function relayTransaction(txHex: string) {
+    return rpcClient.call<{ request_id: number; queued: boolean; tx_hex_len: number }>({
+      method: 'mesh.relay-tx',
+      params: { tx_hex: txHex },
+    })
+  }
+
+  async function relayLightning(bolt11: string, amountSats: number) {
+    return rpcClient.call<{ request_id: number; queued: boolean; amount_sats: number }>({
+      method: 'mesh.relay-lightning',
+      params: { bolt11, amount_sats: amountSats },
+    })
+  }
+
   async function refreshAll() {
-    await Promise.all([fetchStatus(), fetchPeers(), fetchMessages()])
+    await Promise.all([fetchStatus(), fetchPeers(), fetchMessages(), fetchDeadmanStatus(), fetchBlockHeaders()])
   }
 
   return {
@@ -282,6 +354,9 @@ export const useMeshStore = defineStore('mesh', () => {
     sending,
     unreadCounts,
     totalUnread,
+    deadmanStatus,
+    blockHeaders,
+    latestBlockHeight,
     fetchStatus,
     fetchPeers,
     fetchMessages,
@@ -296,5 +371,11 @@ export const useMeshStore = defineStore('mesh', () => {
     sendAlert,
     getSessionStatus,
     rotatePrekeys,
+    fetchDeadmanStatus,
+    configureDeadman,
+    deadmanCheckin,
+    fetchBlockHeaders,
+    relayTransaction,
+    relayLightning,
   }
 })