feat: v1.2.0-alpha — E2E encrypted mesh relay, steganography, relay status polling

Phase 5 mesh networking:
- E2E encrypted TX relay (X25519 + ChaCha20-Poly1305) — non-Archy nodes
  relay encrypted blobs transparently via Meshcore native routing
- Steganographic encoding modes (WeatherStation, SensorNetwork) — traffic
  looks like sensor data on the wire, 0xAA marker, configurable per-node
- Pre-flight Bitcoin Core health check on relay node — specific error codes
  (bitcoin_unreachable, bitcoin_syncing, tx_rejected) instead of generic fails
- mesh.relay-status RPC endpoint — frontend polls for relay result every 3s
- On-Chain / Lightning tabs in Off-Grid Bitcoin panel
- Archy Peers vs Mesh Broadcast relay mode selector
- Mesh view fills viewport (no page scroll), internal panel scrolling
- Version bump to 1.2.0-alpha

Also includes: deploy hardening, container fixes, IndeedHub updates,
boot screen, dashboard improvements, MASTER_PLAN task tracking

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

core/archipelago/src/mesh/bitcoin_relay.rs

@@ -93,6 +93,8 @@ pub struct RelayTracker {
     tx_requests: RwLock<HashMap<u64, PendingRelay>>,
     /// Pending Lightning relay requests.
     lightning_requests: RwLock<HashMap<u64, PendingRelay>>,
+    /// Completed relay results (kept for 5 minutes for frontend polling).
+    completed_results: RwLock<Vec<RelayResult>>,
 }
 
 #[derive(Debug, Clone)]
@@ -101,11 +103,22 @@ struct PendingRelay {
     created_at: String,
 }
 
+/// Result of a completed relay attempt, stored for frontend polling.
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct RelayResult {
+    pub request_id: u64,
+    pub txid: Option<String>,
+    pub error: Option<String>,
+    pub error_code: Option<String>,
+    pub completed_at: String,
+}
+
 impl RelayTracker {
     pub fn new() -> Self {
         Self {
             tx_requests: RwLock::new(HashMap::new()),
             lightning_requests: RwLock::new(HashMap::new()),
+            completed_results: RwLock::new(Vec::new()),
         }
     }
 
@@ -155,6 +168,31 @@ impl RelayTracker {
         let ln = self.lightning_requests.read().await.len();
         (tx, ln)
     }
+
+    /// Store a completed relay result for frontend polling.
+    pub async fn store_result(&self, result: RelayResult) {
+        let mut results = self.completed_results.write().await;
+        // Evict results older than 5 minutes
+        let cutoff = chrono::Utc::now() - chrono::Duration::minutes(5);
+        let cutoff_str = cutoff.to_rfc3339();
+        results.retain(|r| r.completed_at > cutoff_str);
+        results.push(result);
+    }
+
+    /// Get relay result by request_id (returns None if not yet completed or expired).
+    pub async fn get_result(&self, request_id: u64) -> Option<RelayResult> {
+        self.completed_results
+            .read()
+            .await
+            .iter()
+            .find(|r| r.request_id == request_id)
+            .cloned()
+    }
+
+    /// Check if a TX relay request is still pending.
+    pub async fn is_pending(&self, request_id: u64) -> bool {
+        self.tx_requests.read().await.contains_key(&request_id)
+    }
 }
 
 impl Default for RelayTracker {
@@ -220,11 +258,13 @@ pub fn build_tx_relay_response(
     request_id: u64,
     txid: Option<&str>,
     error: Option<&str>,
+    error_code: Option<&str>,
 ) -> Result<Vec<u8>> {
     let payload = message_types::encode_payload(&TxRelayResponsePayload {
         request_id,
         txid: txid.map(|s| s.to_string()),
         error: error.map(|s| s.to_string()),
+        error_code: error_code.map(|s| s.to_string()),
     })?;
     let envelope = TypedEnvelope::new(MeshMessageType::TxRelayResponse, payload);
     envelope.to_wire()