feat(mesh,ui): per-message transport pill (Mesh/FIPS/Tor) + fix E2E pill

Adds a per-message transport badge to archy↔archy mesh chats and fixes the
long-broken E2E badge — both meshcore and meshtastic, styled like the existing
E2E pill.

Transport pill:
- New `MeshMessage.transport` ("lora"/"fips"/"tor"), surfaced in the UI beside
  the E2E badge (Mesh.vue transportLabel() → Mesh/FIPS/Tor, mesh-styles.css).
- Sent LoRa → "lora"; sent federation → finalized to the real leg ("fips"/"tor")
  once the background send resolves (req.send_json transport), via an id-keyed
  store update.
- Received: a post-dispatch stamp on handle_typed_envelope_direct's output
  (monotonic ids) tags both transports without threading through all 20 typed-
  dispatch sites — radio wrapper stamps "lora", federation injector stamps the
  peer's last_transport ("fips"/"tor", default tor; the inbound HTTP carries no
  FIPS-vs-Tor signal).
- Plain native/channel LoRa frames → "lora"; channel broadcasts stay non-E2E.

E2E pill fix:
- `encrypted` was hardcoded false at every MeshMessage construction site, so the
  UI badge (Mesh.vue `v-if="msg.encrypted"`) never showed. Now: federation
  envelopes are E2E (identity-signed over an encrypted transport); the meshcore
  native-DM receive path already had a real `encrypted` flag (now also tagged
  with transport). meshtastic-PKI radio E2E flag threading is a noted follow-up.

Backend cargo check + frontend vue-tsc build both green. Needs a live radio +
multi-transport pass on .116/.228 to confirm end-to-end (see
project_transport_pill / project_meshtastic_parity).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

neode-ui/src/views/Mesh.vue

@@ -1076,6 +1076,17 @@ function isEditedMessage(msg: MeshMessage): number | null {
 function isDeletedMessage(msg: MeshMessage): boolean {
   return msg.message_type === 'delete' || msg.typed_payload?.deleted === true
 }
+/// Short label for the per-message transport pill (Mesh / FIPS / Tor), or null
+/// when the transport isn't known. Covers both meshcore and meshtastic since
+/// the field lives on the shared MeshMessage.
+function transportLabel(msg: MeshMessage): string | null {
+  switch (msg.transport) {
+    case 'lora': return 'Mesh'
+    case 'fips': return 'FIPS'
+    case 'tor': return 'Tor'
+    default: return null
+  }
+}
 
 // Read-receipt: after render, if the bottom message is from the peer (direction='received')
 // and has a MessageKey, fire mesh.send-read-receipt up to that seq. Debounced so scroll
@@ -1798,6 +1809,7 @@ function isImageMime(mime?: string): boolean {
                   <!-- Default: plain text -->
                   <div v-else class="mesh-chat-bubble-text">{{ msg.plaintext }}</div>
                   <div class="mesh-chat-bubble-meta">
+                    <span v-if="transportLabel(msg)" class="mesh-chat-transport" :class="'transport-' + msg.transport" :title="'Delivered over ' + transportLabel(msg)">{{ transportLabel(msg) }}</span>
                     <span v-if="msg.encrypted" class="mesh-chat-e2e">E2E</span>
                     <span v-if="isEditedMessage(msg) !== null" class="mesh-chat-edited">(edited)</span>
                     <span v-if="msg.delivered && msg.direction === 'sent'" class="mesh-chat-ack">&#x2713;&#x2713;</span>