fix(mesh): Reticulum garbage-text + reconnect churn + signal bars + node naming/HTTPS

- reticulum.rs: send_text_msg was lossy-UTF8-mangling binary CBOR control
  envelopes (ReadReceipt etc.) before sending as LXMF text; base64-encode
  with a marker instead, decoded losslessly on receive.
- typed_messages.rs: mesh.send-read-receipt fired automatically on every
  chat view with no is_archy_peer gate, so viewing a message from a stock
  (non-archy) LXMF peer auto-sent it an undecodable control envelope,
  surfacing as garbage text right after whatever it just sent. Now a no-op
  for non-archy peers.
- mesh/listener/mod.rs: RX_STALL_TIMEOUT was 300s and forced a full
  auto-detect reconnect on any otherwise-healthy but quiet mesh link
  (visible as "Connecting..." flapping); this also wiped Reticulum's
  in-memory peer-address table every cycle, breaking messaging with peers
  who hadn't re-announced in the window. Bumped to 1800s.
- reticulum.rs: persist the peer prefix/dest-hash/display-name table to
  disk so a restart doesn't force every peer back to "Anonymous Peer"
  until they re-announce.
- decode.rs/frames.rs: Meshcore was discarding the SNR its wire format
  carries; wire it onto the peer record. Mesh.vue's signalBars() now falls
  back to SNR-based bars when RSSI is unavailable (always true for
  Meshcore); Reticulum has neither and correctly stays at 0/"no data".
- system/handlers.rs, dispatcher.rs: new system.get-hostname RPC + cert
  regeneration (with a proper SAN) whenever server.set-name changes the
  hostname, so HTTPS doesn't add a mismatch warning on top of the
  self-signed one after a rename.
- AccountInfoSection.vue: surface the mDNS hostname + http/https links in
  Settings (HTTPS needed for mic/camera secure-context features) — never
  forced, both keep working.
- build-auto-installer-iso.sh: ship avahi-daemon so .local names actually
  resolve on the LAN, and give the self-signed cert a real SAN instead of
  a bare CN, both at image-build and install-time-fallback.
- Mesh.vue/MediaLightbox.vue/mesh-styles.css: mic/attach-stack no longer
  closes on a plain hover-past; mesh images open in the shared lightbox
  and have a real download button; lightbox close button moves to
  bottom-center on mobile instead of under the status bar; mesh device
  panel gets the same height/padding as its sibling tabs.

Verified: 108/108 mesh unit tests, deployed + confirmed healthy on
.116/.198/.228 (matching binary hash across all three), live Reticulum
messaging confirmed working end-to-end post-deploy.

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

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

@@ -933,6 +933,15 @@ impl RpcHandler {
         let svc = service
             .as_ref()
             .ok_or_else(|| anyhow::anyhow!("Mesh service not running"))?;
+        // Read receipts are fired automatically just by viewing a chat (no
+        // explicit user action), unlike every other typed send here — so a
+        // stock (non-archy) peer that can't decode a TypedEnvelope at all
+        // (e.g. a phone running plain Sideband) would otherwise get a raw
+        // control envelope shoved at it the moment its message is viewed,
+        // surfacing as garbage text right after whatever it just sent.
+        if !svc.is_archy_peer(contact_id).await {
+            return Ok(serde_json::json!({ "sent": false, "reason": "not an archy peer" }));
+        }
         let seq = svc.next_send_seq(contact_id).await;
         let payload = message_types::encode_payload(&receipt)?;
         let envelope = TypedEnvelope::new(MeshMessageType::ReadReceipt, payload).with_seq(seq);