fix(queue): preserve lifecycle ownership during recovery

Require queue-permit ownership before resuming a paused GID and rebuild a job when its GID disappears during recovery.

Advance the Browser companion with the automatic-capture handoff guard for #28.

src-tauri/src/lib.rs

@@ -4598,7 +4598,7 @@ async fn resume_download(
                     return;
                 }
                 if let Some(permit) = permit_candidate {
-                    let _ = queue_manager
+                    let parked = queue_manager
                         .park_aria2_permit_if_missing_for_queue(
                             &id_clone,
                             &queue_id,
@@ -4606,6 +4606,14 @@ async fn resume_download(
                             permit,
                         )
                         .await;
+                    if !parked {
+                        log::warn!(
+                            "aria2 resume [{}]: permit ownership was not established before unpause; leaving gid {} paused",
+                            id_clone,
+                            gid_clone
+                        );
+                        return;
+                    }
                 }
                 let _ = app_handle_clone.emit(
                     "download-state",

src-tauri/src/queue.rs

@@ -118,6 +118,10 @@ pub enum Aria2RecreateOutcome {
     Unavailable(String),
 }
 
+fn aria2_recovery_should_rebuild_after_pause_error(status: &str) -> bool {
+    status == "removed"
+}
+
 /// What kind of sidecar a queued task spawns. Drives which runner the
 /// dispatcher invokes.
 #[derive(Debug, Clone)]
@@ -2824,6 +2828,16 @@ impl SidecarSpawner for ProductionSpawner {
                             Ok(status) if status == "complete" => {
                                 return Ok(Aria2RecreateOutcome::Complete);
                             }
+                            Ok(status)
+                                if aria2_recovery_should_rebuild_after_pause_error(&status) =>
+                            {
+                                log::warn!(
+                                    "aria2 connection recovery [{}]: gid {} disappeared after forcePause failed; rebuilding from the saved payload: {}",
+                                    id,
+                                    gid,
+                                    error
+                                );
+                            }
                             Ok(status) => {
                                 return Err(format!(
                                     "failed to pause aria2 gid {gid} before recreation: {error}; daemon reports {status}"
@@ -3128,6 +3142,13 @@ mod tests {
         );
     }
 
+    #[test]
+    fn aria2_recovery_rebuilds_when_force_pause_races_with_removal() {
+        assert!(aria2_recovery_should_rebuild_after_pause_error("removed"));
+        assert!(!aria2_recovery_should_rebuild_after_pause_error("paused"));
+        assert!(!aria2_recovery_should_rebuild_after_pause_error("active"));
+    }
+
     #[test]
     fn aria2_connection_options_clamp_untrusted_connection_counts() {
         let mut options = serde_json::Map::new();