feat(companion): mesh party + Flare, keep-warm mesh, restored fast-start, UI fixes — 0.5.7

Combined session state from both agents (shared checkout):

- Mesh Party / Flare (experimental): phone-to-phone FIPS via party QR,
  Flare chat/beam on :5680, optional fixed UDP listen (2121); party-only
  phones get the baked-in Archipelago anchor so two bare phones reach
  each other across the internet, not just on a hotspot.
- Keep-warm mesh: a running healthy node survives app opens (restart
  only when dead or peers changed — peersDirty); requestMeshRestart for
  config changes. Cold start measured on-device: session in ~3.1s.
- Restored after regression: startup LAN-vs-mesh race (the party work
  was based on a pre-#114 file copy) and same-node routing (BTCPay/
  Pine/HA had returned to opening in the external browser).
- UI: top status-bar scrim removed (bottom-only bars); web app-session
  mobile bar is solid black — app theme colour no longer bleeds through
  the bar and its safe-area strip.

Served APK: 0.5.7 (vc27).

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

neode-ui/src/views/AppSession.vue

@@ -685,9 +685,9 @@ onBeforeUnmount(() => {
   min-height: var(--app-session-mobile-bar-height, 84px);
   padding: 10px 16px;
   padding-bottom: calc(10px + max(var(--safe-area-bottom, 0px), env(safe-area-inset-bottom, 0px), 10px));
-  background: rgba(0, 0, 0, 0.25);
-  backdrop-filter: blur(18px);
-  -webkit-backdrop-filter: blur(18px);
+  /* Solid black, not translucent: the app iframe's theme colour bled
+     through the bar and its safe-area strip on phones. */
+  background: #000;
   border-top: 1px solid rgba(255, 255, 255, 0.06);
   transform: translateZ(0);
 }