feat(settings): per-service FIPS/Tor transport preference

Adds a user-configurable toggle for how each peer-to-peer service
reaches federated peers. Three options per service:

- Auto (default) — FIPS preferred, Tor fallback (current behavior).
- FIPS only — fail rather than fall through to Tor.
- Tor only — explicit opt-in to onion anonymity for that service.

Services covered (matching the UI rows):
- Federation — state sync, invites, peer notifications
- Peers — address/DID rotation broadcasts
- Peer Files — content catalog download/browse/preview
- Messaging — archipelago channel + mesh bridge
- Mesh File Sharing — content_ref blob fetches

Implementation:
- settings::transport — persisted struct + process-wide OnceLock handle
  (so deep call sites don't need data_dir threaded through signatures).
  On-disk file: <data_dir>/settings/transport_preferences.json; missing
  or corrupt → defaults (Auto everywhere).
- settings::transport::init() called from main.rs after config load.
- fips::dial::PeerRequest gains a .service(kind) builder; send_* checks
  the preference before choosing a transport. FIPS-only fails loudly
  when FIPS is unavailable (so users who pick it know when something
  falls back).
- Every FIPS-first migration site tags its PeerRequest with the
  matching PeerService so the toggle actually applies.
- transport.preferences + transport.set-preference RPCs added; wired
  into the dispatcher.
- neode-ui/src/views/settings/TransportPrefsCard.vue — standalone card
  with a 5-row Auto/FIPS/Tor tri-state. Not wired into Settings.vue —
  the user places components themselves (see feedback_ui_entry_points).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

core/archipelago/src/node_message.rs

@@ -280,6 +280,7 @@ pub async fn send_to_peer(
         onion,
         "/archipelago/node-message",
     )
+    .service(crate::settings::transport::PeerService::Messaging)
     .timeout(std::time::Duration::from_secs(60))
     .send_json(&body)
     .await
@@ -310,6 +311,7 @@ pub async fn send_to_peer(
 pub async fn check_peer_reachable(onion: &str, fips_npub: Option<&str>) -> Result<bool> {
     validate_onion(onion)?;
     match crate::fips::dial::PeerRequest::new(fips_npub, onion, "/health")
+        .service(crate::settings::transport::PeerService::Messaging)
         .timeout(std::time::Duration::from_secs(30))
         .send_get()
         .await