fix(mesh): first-class Reticulum — probe boot-race, live config apply, name propagation, daemon-death detection

Root causes found and fixed after live debugging on archi-dev-box (all
verified on real RNode hardware, archi-dev-box <-> archy-x250-dev E2E):

- probe_rnode raced the board's own boot: opening the port pulses DTR/RTS
  through USB-UART bridges (CP2102/Heltec V3), the ESP32 power-cycles and
  spends ~2.5-3s in boot ROM, and the KISS DETECT written 300ms after open
  landed in the void — so an RNode could NEVER connect on these boards.
  Now: immediate probe (fast path), then drain-until-quiet boot settle and
  a second DETECT with a fresh response window.
- MeshService::configure() only restarted the listener on enable/disable —
  device_kind/device_path/advert_name/RF-param changes were silent no-ops
  until a full process restart (the setup modal's apply/keep-as-is did
  nothing). Material config changes now bounce the listener; the open
  sequence races the shutdown signal so stop() no longer burns the full
  15s timeout mid-probe; mesh.configure applies in the background instead
  of stalling every status poll behind the service write-lock.
- The mesh name was write-only: config.advert_name had no reader,
  server.set-name never reached the mesh service, and Reticulum's
  set_advert_name was a no-op (daemon display name fixed at spawn, and the
  ARCHY:2 announce blob REPLACED the LXMF display name — every archy node
  was anonymous on RNS). Now: advert_name > server name precedence feeds
  the session, renames restart it live, the daemon gets --display-name at
  spawn plus a set_name RPC verb, and announces carry the LXMF-standard
  msgpack name with the identity blob appended as an extra list element
  stock clients (Sideband/NomadNet) ignore.
- Dead reticulum-daemon was invisible for up to 30min (RX-stall watchdog):
  child exit / RPC-EOF now fails try_recv_frame so the session reconnects.
- Setup modal re-trigger loop: plugged_at used the tty node's mtime, which
  bumps on every open — each probe invalidated the dismissal key. Use
  btime/ctime (only change on real plugs).
- ARCHY:2 identity adverts (re-emitted every 60s over Reticulum) stomped
  the federation twin's real name with a synthetic Archy-… placeholder and
  nulled its position; blob-only announces no longer assert a name, blob
  strings can never become display names, and stale blob names are healed
  at peers.json load.
- mesh.broadcast on Meshtastic sent heartbeat+time only (no identity);
  SendAdvert now also fires a want_response NodeInfo broadcast.
- New mesh.refresh RPC: actively re-queries the radio contact table (the
  UI Refresh button previously only re-read server caches).
- Reticulum peers now track last_advert (announce time) and mark existing
  peers reachable on inbound traffic.
- Boot auto-enable no longer force-enables mesh when an operator
  explicitly disabled it (only fires when no config file exists).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

core/archipelago/src/api/rpc/mesh/messaging.rs

@@ -1,6 +1,7 @@
 use super::super::RpcHandler;
 use crate::mesh;
 use anyhow::Result;
+use std::sync::Arc;
 use tracing::info;
 
 impl RpcHandler {
@@ -131,7 +132,14 @@ impl RpcHandler {
             config.broadcast_identity = broadcast;
         }
         if let Some(name) = params.get("advert_name").and_then(|v| v.as_str()) {
-            config.advert_name = Some(name.to_string());
+            // Empty clears the custom mesh name (falls back to the server
+            // name) — without this, a name could be set but never unset.
+            let trimmed = name.trim();
+            config.advert_name = if trimmed.is_empty() {
+                None
+            } else {
+                Some(trimmed.to_string())
+            };
         }
         if let Some(announce) = params
             .get("announce_block_headers")
@@ -202,10 +210,24 @@ impl RpcHandler {
 
         mesh::save_config(&self.config.data_dir, &config).await?;
 
-        // If we have a running service, update its config
-        let mut service = self.mesh_service.write().await;
-        if let Some(svc) = service.as_mut() {
-            svc.configure(config.clone()).await?;
+        // Apply to the running service in the background: configure() may
+        // stop+start the listener (config changes now restart the session so
+        // they actually take effect), and that can take seconds when the old
+        // session is mid-probe. Holding the service write-lock for that long
+        // inside this handler stalled every concurrent mesh.status/mesh.peers
+        // poll behind it — the UI froze and nginx surfaced 502s. The config is
+        // already persisted above; the UI observes progress via mesh.status.
+        {
+            let service_arc = Arc::clone(&self.mesh_service);
+            let config_for_apply = config.clone();
+            tokio::spawn(async move {
+                let mut service = service_arc.write().await;
+                if let Some(svc) = service.as_mut() {
+                    if let Err(e) = svc.configure(config_for_apply).await {
+                        tracing::error!("Applying mesh config to running service failed: {e:#}");
+                    }
+                }
+            });
         }
 
         info!("Mesh config updated");

core/archipelago/src/api/rpc/mesh/status.rs

@@ -110,6 +110,28 @@ impl RpcHandler {
         Ok(serde_json::to_value(probe)?)
     }
 
+    /// mesh.refresh — Actively refresh discovery state: re-query the radio's
+    /// contact table and re-announce ourselves so quiet-but-alive neighbours
+    /// answer. This is what the UI's Refresh button calls — before it existed
+    /// the button only re-read server caches and never touched the radio.
+    pub(in crate::api::rpc) async fn handle_mesh_refresh(&self) -> Result<serde_json::Value> {
+        let service = self.mesh_service.read().await;
+        let Some(svc) = service.as_ref() else {
+            return Ok(serde_json::json!({ "refreshed": false, "device_connected": false }));
+        };
+        let status = svc.status().await;
+        if status.device_connected {
+            let state = svc.shared_state();
+            let _ = state
+                .send_cmd(crate::mesh::listener::MeshCommand::RefreshContacts)
+                .await;
+        }
+        Ok(serde_json::json!({
+            "refreshed": status.device_connected,
+            "device_connected": status.device_connected,
+        }))
+    }
+
     /// mesh.peers — List discovered mesh peers.
     pub(in crate::api::rpc) async fn handle_mesh_peers(&self) -> Result<serde_json::Value> {
         let service = self.mesh_service.read().await;