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>

Android/rust/archy-fips-core/Cargo.toml

@@ -0,0 +1,43 @@
+# Embedded FIPS mesh node for the Archipelago companion app.
+#
+# Built for Android via cargo-ndk (see Android/app/build.gradle.kts, task
+# buildRustArm64) into app/src/main/jniLibs/arm64-v8a/libarchy_fips_core.so.
+# Also builds on the host so `cargo test` covers the non-JNI logic.
+#
+# `fips` is pinned to the fips-native fork rev that this integration was
+# developed against — the fork carries Android support upstream lacks
+# (Tun::from_fd for a VpnService-owned fd, cfg(target_os = "android") paths).
+# Override with a local checkout when hacking on fips itself:
+#   CARGO_NET_OFFLINE=false cargo ndk ... --config 'patch."https://github.com/9qeklajc/fips-native".fips.path="/path/to/fips-native/fips"'
+[package]
+name = "archy-fips-core"
+version = "0.1.0"
+edition = "2021"
+license = "MIT"
+publish = false
+
+[lib]
+name = "archy_fips_core"
+# rlib for host tests; cdylib for the Android shared library.
+crate-type = ["lib", "cdylib"]
+
+[dependencies]
+# default-features drops the ratatui TUI; tun-support enables Node::start_with_tun_fd.
+fips = { git = "https://github.com/9qeklajc/fips-native", rev = "46494a74fc85b878305d275d42ab719082b06ba6", default-features = false, features = ["tun-support"] }
+anyhow = "1.0"
+serde_json = "1.0"
+hex = "0.4"
+# OS CSPRNG for identity generation (crypto rule: no thread-local RNG for keys).
+getrandom = "0.2"
+tokio = { version = "1", features = ["rt-multi-thread", "sync", "time", "macros"] }
+tracing = "0.1"
+
+# The JNI surface only exists on Android; host builds skip it and drive the
+# mesh module directly (tests).
+[target.'cfg(target_os = "android")'.dependencies]
+jni = "0.21"
+# Bridge `tracing` (ours + fips) to logcat: `adb logcat -s archy-fips`.
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+paranoid-android = "0.2"
+
+[workspace]

Android/rust/archy-fips-core/src/jni_glue.rs

@@ -0,0 +1,126 @@
+//! JNI surface for `com.archipelago.app.fips.FipsNative` — JSON over strings,
+//! no codegen (the myco / nostr-vpn embedding pattern). Errors come back as
+//! `{"error": "…"}` so Kotlin never sees a raw exception from native code.
+
+use std::sync::Once;
+
+use jni::objects::{JClass, JString};
+use jni::sys::{jboolean, jint, jstring};
+use jni::JNIEnv;
+
+use crate::mesh;
+
+static LOG_INIT: Once = Once::new();
+
+fn init_logging() {
+    LOG_INIT.call_once(|| {
+        use tracing_subscriber::layer::SubscriberExt;
+        use tracing_subscriber::util::SubscriberInitExt;
+        let _ = tracing_subscriber::registry()
+            .with(tracing_subscriber::EnvFilter::new("info"))
+            .with(paranoid_android::layer("archy-fips"))
+            .try_init();
+    });
+}
+
+fn jstr(env: &mut JNIEnv, s: &JString) -> String {
+    env.get_string(s).map(|s| s.into()).unwrap_or_default()
+}
+
+fn out(env: &JNIEnv, s: String) -> jstring {
+    env.new_string(s)
+        .map(|s| s.into_raw())
+        .unwrap_or(std::ptr::null_mut())
+}
+
+fn err_json(e: impl std::fmt::Display) -> String {
+    serde_json::json!({ "error": e.to_string() }).to_string()
+}
+
+fn identity_json(info: &mesh::IdentityInfo) -> String {
+    serde_json::json!({
+        "secret": info.secret_hex,
+        "npub": info.npub,
+        "address": info.address,
+    })
+    .to_string()
+}
+
+/// Kotlin: `external fun generateIdentity(): String`
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_fips_FipsNative_generateIdentity(
+    env: JNIEnv,
+    _class: JClass,
+) -> jstring {
+    init_logging();
+    let json = match mesh::generate_identity() {
+        Ok(info) => identity_json(&info),
+        Err(e) => err_json(e),
+    };
+    out(&env, json)
+}
+
+/// Kotlin: `external fun deriveIdentity(secret: String): String`
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_fips_FipsNative_deriveIdentity(
+    mut env: JNIEnv,
+    _class: JClass,
+    secret: JString,
+) -> jstring {
+    init_logging();
+    let secret = jstr(&mut env, &secret);
+    let json = match mesh::derive_identity(&secret) {
+        Ok(info) => identity_json(&info),
+        Err(e) => err_json(e),
+    };
+    out(&env, json)
+}
+
+/// Kotlin: `external fun start(secret: String, peersJson: String, tunFd: Int): String`
+/// Returns `{"npub": "...", "address": "..."}` or `{"error": "..."}`.
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_fips_FipsNative_start(
+    mut env: JNIEnv,
+    _class: JClass,
+    secret: JString,
+    peers_json: JString,
+    tun_fd: jint,
+) -> jstring {
+    init_logging();
+    let secret = jstr(&mut env, &secret);
+    let peers = jstr(&mut env, &peers_json);
+    let json = match mesh::start(&secret, &peers, tun_fd) {
+        Ok((npub, address)) => {
+            serde_json::json!({ "npub": npub, "address": address }).to_string()
+        }
+        Err(e) => err_json(e),
+    };
+    out(&env, json)
+}
+
+/// Kotlin: `external fun stop()`
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_fips_FipsNative_stop(
+    _env: JNIEnv,
+    _class: JClass,
+) {
+    mesh::stop();
+}
+
+/// Kotlin: `external fun isRunning(): Boolean`
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_fips_FipsNative_isRunning(
+    _env: JNIEnv,
+    _class: JClass,
+) -> jboolean {
+    mesh::is_running() as jboolean
+}
+
+/// Kotlin: `external fun statusJson(): String`
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_fips_FipsNative_statusJson(
+    env: JNIEnv,
+    _class: JClass,
+) -> jstring {
+    out(&env, mesh::status_json())
+}

Android/rust/archy-fips-core/src/lib.rs

@@ -0,0 +1,17 @@
+//! Embedded FIPS mesh node for the Archipelago companion app.
+//!
+//! The phone runs a real, leaf-only FIPS node in-process: Android's
+//! `VpnService` owns the TUN fd (routing only `fd00::/8`, so normal traffic
+//! never touches the tunnel) and hands it to [`fips::Node::start_with_tun_fd`].
+//! Peering is outbound-only — the pairing QR carries the node's npub and
+//! transport endpoints, and FIPS nodes accept inbound peers without prior
+//! registration, so no server-side enrollment step exists.
+//!
+//! The JNI surface (`jni_glue`, Android-only) is deliberately tiny and
+//! JSON-over-strings, mirroring the myco / nostr-vpn embedding pattern:
+//! `generateIdentity`, `deriveIdentity`, `start`, `stop`, `isRunning`.
+
+pub mod mesh;
+
+#[cfg(target_os = "android")]
+mod jni_glue;

Android/rust/archy-fips-core/src/mesh.rs

@@ -0,0 +1,245 @@
+//! Mesh lifecycle: identity, config assembly, and the node task.
+//!
+//! Host-buildable (no JNI) so the config/identity logic is unit-testable;
+//! only [`start`] needs a real TUN fd and therefore only runs on-device.
+
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::{Arc, Mutex};
+use std::time::Duration;
+
+use anyhow::{anyhow, Context, Result};
+use fips::config::{PeerConfig, TransportInstances, UdpConfig};
+use fips::{Config, Identity, Node};
+use tokio::sync::Notify;
+
+/// How long `start` waits for the node to come up (TUN attach + transports).
+const START_TIMEOUT: Duration = Duration::from_secs(15);
+
+/// How long `stop` waits for the node task to drain.
+const STOP_TIMEOUT: Duration = Duration::from_secs(5);
+
+struct MeshHandle {
+    runtime: tokio::runtime::Runtime,
+    task: Option<tokio::task::JoinHandle<()>>,
+    shutdown: Arc<Notify>,
+    running: Arc<AtomicBool>,
+    npub: String,
+    address: String,
+}
+
+static MESH: Mutex<Option<MeshHandle>> = Mutex::new(None);
+
+#[derive(Debug, Clone)]
+pub struct IdentityInfo {
+    pub secret_hex: String,
+    pub npub: String,
+    /// The phone's own ULA on the mesh (fd::/8), for VpnService.addAddress.
+    pub address: String,
+}
+
+/// Generate a fresh mesh identity from the OS CSPRNG.
+pub fn generate_identity() -> Result<IdentityInfo> {
+    // ~1 in 2^128 chance a candidate is off the curve; loop regardless.
+    loop {
+        let mut bytes = [0u8; 32];
+        getrandom::getrandom(&mut bytes).context("OS RNG")?;
+        if let Ok(id) = Identity::from_secret_bytes(&bytes) {
+            return Ok(IdentityInfo {
+                secret_hex: hex::encode(bytes),
+                npub: id.npub(),
+                address: id.address().to_ipv6().to_string(),
+            });
+        }
+    }
+}
+
+/// Re-derive npub + ULA from a stored secret.
+pub fn derive_identity(secret: &str) -> Result<IdentityInfo> {
+    let id = Identity::from_secret_str(secret).map_err(|e| anyhow!("bad secret: {e}"))?;
+    Ok(IdentityInfo {
+        secret_hex: secret.to_string(),
+        npub: id.npub(),
+        address: id.address().to_ipv6().to_string(),
+    })
+}
+
+/// Build the phone-side node config: leaf-only (never routes third-party
+/// traffic — battery), ephemeral outbound-only transports, no DNS responder,
+/// TUN enabled but attached to the VpnService fd rather than created.
+pub fn build_config(secret: &str, peers: Vec<PeerConfig>) -> Config {
+    let mut cfg = Config::default();
+    cfg.node.identity.nsec = Some(secret.to_string());
+    cfg.node.identity.persistent = false;
+    cfg.node.leaf_only = true;
+    cfg.tun.enabled = true;
+    cfg.tun.mtu = Some(1280);
+    cfg.dns.enabled = false;
+    // Ephemeral UDP port: outbound dialing works, nothing predictable listens.
+    cfg.transports.udp = TransportInstances::Single(UdpConfig {
+        bind_addr: Some("0.0.0.0:0".to_string()),
+        ..Default::default()
+    });
+    // TCP with no bind_addr = outbound-only (fallback when UDP is blocked).
+    cfg.transports.tcp = TransportInstances::Single(Default::default());
+    cfg.peers = peers;
+    cfg
+}
+
+/// Parse the peers JSON handed over from Kotlin. Shape = fips `PeerConfig`:
+/// `[{"npub":"…","alias":"…","addresses":[{"transport":"udp","addr":"host:2121","priority":10},…]}]`
+pub fn parse_peers(peers_json: &str) -> Result<Vec<PeerConfig>> {
+    serde_json::from_str(peers_json).context("peers JSON")
+}
+
+/// Start the mesh node on the given TUN fd (from `VpnService.establish()`,
+/// detached — the node owns it from here). Returns (npub, ula) on success.
+/// Any previously running node is stopped first.
+pub fn start(secret: &str, peers_json: &str, tun_fd: i32) -> Result<(String, String)> {
+    stop();
+
+    let peers = parse_peers(peers_json)?;
+    let config = build_config(secret, peers);
+    let mut node = Node::new(config).map_err(|e| anyhow!("node init: {e}"))?;
+    let npub = node.npub();
+    let address = node.identity().address().to_ipv6().to_string();
+
+    let runtime = tokio::runtime::Builder::new_multi_thread()
+        .worker_threads(2)
+        .enable_all()
+        .thread_name("archy-fips")
+        .build()
+        .context("tokio runtime")?;
+
+    let shutdown = Arc::new(Notify::new());
+    let running = Arc::new(AtomicBool::new(false));
+    let (started_tx, started_rx) = tokio::sync::oneshot::channel::<Result<()>>();
+
+    let task = {
+        let shutdown = shutdown.clone();
+        let running = running.clone();
+        runtime.spawn(async move {
+            match node.start_with_tun_fd(tun_fd).await {
+                Ok(()) => {
+                    running.store(true, Ordering::SeqCst);
+                    let _ = started_tx.send(Ok(()));
+                }
+                Err(e) => {
+                    let _ = started_tx.send(Err(anyhow!("node start: {e}")));
+                    return;
+                }
+            }
+            tokio::select! {
+                result = node.run_rx_loop() => {
+                    if let Err(e) = result {
+                        tracing::error!("mesh rx loop error: {e}");
+                    }
+                }
+                _ = shutdown.notified() => {}
+            }
+            if let Err(e) = node.stop().await {
+                tracing::warn!("mesh stop: {e}");
+            }
+            running.store(false, Ordering::SeqCst);
+        })
+    };
+
+    let started = runtime
+        .block_on(async { tokio::time::timeout(START_TIMEOUT, started_rx).await })
+        .map_err(|_| anyhow!("node start timed out"))?
+        .map_err(|_| anyhow!("node task died during start"))?;
+    if let Err(e) = started {
+        runtime.shutdown_background();
+        return Err(e);
+    }
+
+    *MESH.lock().unwrap() = Some(MeshHandle {
+        runtime,
+        task: Some(task),
+        shutdown,
+        running,
+        npub: npub.clone(),
+        address: address.clone(),
+    });
+    Ok((npub, address))
+}
+
+/// Stop the mesh node if running. Idempotent.
+pub fn stop() {
+    let Some(mut handle) = MESH.lock().unwrap().take() else {
+        return;
+    };
+    handle.shutdown.notify_waiters();
+    if let Some(task) = handle.task.take() {
+        let _ = handle
+            .runtime
+            .block_on(async { tokio::time::timeout(STOP_TIMEOUT, task).await });
+    }
+    handle.runtime.shutdown_background();
+}
+
+pub fn is_running() -> bool {
+    MESH.lock()
+        .unwrap()
+        .as_ref()
+        .map(|h| h.running.load(Ordering::SeqCst))
+        .unwrap_or(false)
+}
+
+/// `{running, npub, address}` for the Kotlin status surface.
+pub fn status_json() -> String {
+    let guard = MESH.lock().unwrap();
+    match guard.as_ref() {
+        Some(h) => serde_json::json!({
+            "running": h.running.load(Ordering::SeqCst),
+            "npub": h.npub,
+            "address": h.address,
+        })
+        .to_string(),
+        None => serde_json::json!({ "running": false }).to_string(),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn identity_roundtrip() {
+        let a = generate_identity().unwrap();
+        let b = derive_identity(&a.secret_hex).unwrap();
+        assert_eq!(a.npub, b.npub);
+        assert_eq!(a.address, b.address);
+        // ULA in fd::/8
+        assert!(a.address.starts_with("fd"));
+    }
+
+    #[test]
+    fn peers_json_parses_into_peer_config() {
+        let peers = parse_peers(
+            r#"[{
+                "npub": "npub1abc",
+                "alias": "My Archipelago",
+                "addresses": [
+                    {"transport": "udp", "addr": "192.168.1.228:2121", "priority": 10},
+                    {"transport": "tcp", "addr": "192.168.1.228:8443", "priority": 20}
+                ]
+            }]"#,
+        )
+        .unwrap();
+        assert_eq!(peers.len(), 1);
+        assert_eq!(peers[0].addresses.len(), 2);
+        assert!(peers[0].is_auto_connect());
+    }
+
+    #[test]
+    fn config_is_leaf_only_with_tun() {
+        let id = generate_identity().unwrap();
+        let cfg = build_config(&id.secret_hex, vec![]);
+        assert!(cfg.node.leaf_only);
+        assert!(cfg.tun.enabled);
+        assert_eq!(cfg.tun.mtu(), 1280);
+        assert!(!cfg.dns.enabled);
+        assert!(!cfg.transports.udp.is_empty());
+        assert!(!cfg.transports.tcp.is_empty());
+    }
+}