feat: instant companion pairing — device tokens, named QR, FIPS pair-info

- auth.createDeviceToken / listDeviceTokens / revokeDeviceToken RPCs; only
  SHA-256 hashes persist in data_dir/device-tokens.json
- auth.login accepts {token} (same rate limiter, skips TOTP like remember-me)
- pairing QR now carries name (server name, fallback "My Archipelago"),
  tok (instant login), and FIPS mesh params from new fips.pair-info RPC
  (npub, fips0 ULA, transport ports)
- companion onboarding drops the WireGuard install/tunnel screens — remote
  access moves to the FIPS mesh embedded in the companion app
- fix: fips daemon UDP bind now 2121, matching the published container port
  and fleet rosters (was upstream's 8668 — inbound UDP was dead on bridged
  installs, mesh silently rode TCP 8443)

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

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

@@ -9,6 +9,23 @@ impl RpcHandler {
         params: Option<serde_json::Value>,
     ) -> Result<serde_json::Value> {
         let params = params.ok_or_else(|| anyhow::anyhow!("Missing params"))?;
+
+        // Companion device-token login: minted via auth.createDeviceToken and
+        // carried by the pairing QR. Verified here so it shares the login rate
+        // limiter with password attempts.
+        if let Some(token) = params.get("token").and_then(|v| v.as_str()) {
+            return match crate::device_tokens::verify(&self.config.data_dir, token).await {
+                Some(device) => {
+                    tracing::info!("[onboarding] device-token login ({device})");
+                    Ok(serde_json::Value::Null)
+                }
+                None => {
+                    tracing::warn!("[onboarding] device-token login failed");
+                    Err(anyhow::anyhow!("Invalid device token"))
+                }
+            };
+        }
+
         let password = params
             .get("password")
             .and_then(|v| v.as_str())
@@ -73,6 +90,48 @@ impl RpcHandler {
         Ok(serde_json::Value::Null)
     }
 
+    /// Mint a device token for the companion pairing QR. Session-gated by the
+    /// dispatcher (not in UNAUTHENTICATED_METHODS), so only a logged-in web UI
+    /// can mint one. The plaintext token is returned exactly once.
+    pub(super) async fn handle_auth_create_device_token(
+        &self,
+        params: Option<serde_json::Value>,
+    ) -> Result<serde_json::Value> {
+        let name = params
+            .as_ref()
+            .and_then(|p| p.get("name"))
+            .and_then(|v| v.as_str())
+            .unwrap_or("companion")
+            .trim()
+            .to_string();
+        if name.is_empty() || name.len() > 64 {
+            return Err(anyhow::anyhow!("Device name must be 1-64 characters"));
+        }
+        let token = crate::device_tokens::create(&self.config.data_dir, &name).await?;
+        Ok(serde_json::json!({ "name": name, "token": token }))
+    }
+
+    pub(super) async fn handle_auth_list_device_tokens(&self) -> Result<serde_json::Value> {
+        let tokens = crate::device_tokens::list(&self.config.data_dir).await;
+        Ok(serde_json::json!(tokens
+            .iter()
+            .map(|t| serde_json::json!({ "name": t.name, "created": t.created }))
+            .collect::<Vec<_>>()))
+    }
+
+    pub(super) async fn handle_auth_revoke_device_token(
+        &self,
+        params: Option<serde_json::Value>,
+    ) -> Result<serde_json::Value> {
+        let name = params
+            .as_ref()
+            .and_then(|p| p.get("name"))
+            .and_then(|v| v.as_str())
+            .ok_or_else(|| anyhow::anyhow!("Missing name"))?;
+        let removed = crate::device_tokens::remove(&self.config.data_dir, name).await?;
+        Ok(serde_json::json!({ "removed": removed }))
+    }
+
     pub(super) async fn handle_auth_logout(&self) -> Result<serde_json::Value> {
         tracing::info!("[onboarding] logout");
         Ok(serde_json::Value::Null)