feat(companion): embedded FIPS mesh replaces WireGuard for remote access

- Android/rust/archy-fips-core: leaf-only fips node as a JNI cdylib (fips
  pinned to the fips-native fork rev with VpnService fd support), built by
  gradle via cargo-ndk (arm64), tested on host
- ArchyVpnService: split-tunnel VpnService routing only fd00::/8 (MTU 1280,
  foreground specialUse); FipsManager handles the one-time VPN consent and
  silent auto-start — no settings surface at all
- pairing QR now fully configures the mesh: fnpub/fip/fhost/fudp/ftcp plus
  fanchors (the node's seed-anchor list, npub@addr/transport) so the phone
  can rendezvous through public anchors when the LAN endpoint is unreachable
- default seed anchors gain the two dual-transport join.fips.network test
  anchors (23.182.128.74:443/tcp, 217.77.8.91:443/tcp); anchor adverts are
  Nostr kind-37195 events
- device token rides the password field end-to-end: backend accepts tokens
  wherever it accepts the password, so scan = instant login (WebSocket auth
  + WebView form injection unchanged); token logins skip TOTP
- ServerEntry.meshIp + IPv6-bracketed URLs; WebView retries the mesh address
  on main-frame errors, auto-login and origin checks honor it
- companion v0.5.0 (versionCode 20), arm64 abiFilter; FipsNative.available
  gates everything so non-arm64 still runs as a plain companion

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

core/archipelago/src/api/rpc/fips.rs

@@ -27,11 +27,27 @@ impl RpcHandler {
             anyhow::anyhow!("FIPS identity not provisioned yet — complete onboarding first")
         })?;
         let ula = fips::iface::fips0_ula().map(|ip| ip.to_string());
+        // The node's seed anchors ride along so the phone can rendezvous
+        // through the same public mesh points when the node's LAN endpoint
+        // isn't directly dialable (phone away from home, node behind NAT).
+        let anchors = fips::anchors::load(&self.config.data_dir)
+            .await
+            .unwrap_or_default()
+            .into_iter()
+            .map(|a| {
+                serde_json::json!({
+                    "npub": a.npub,
+                    "addr": a.address,
+                    "transport": a.transport,
+                })
+            })
+            .collect::<Vec<_>>();
         Ok(serde_json::json!({
             "npub": npub,
             "ula": ula,
             "udp_port": fips::PUBLISHED_UDP_PORT,
             "tcp_port": fips::DEFAULT_TCP_PORT,
+            "anchors": anchors,
         }))
     }