feat(#2102): skip startup rebuild for stopped/unchanged containers

hive-c0re/src/socket_server.rs

@@ -803,6 +803,25 @@ async fn handle_start(coord: &Arc<Coordinator>, agent: &str, name: &str) -> Agen
         return err;
     }
     tracing::info!(%agent, %name, "start container");
+    // If the hyperhive rev is stale, route through the rebuild queue so the
+    // container runs current nix derivations before it starts. Same logic as
+    // `run_start`; this covers the MCP `start` tool path.
+    let current_rev = crate::auto_update::current_flake_rev(&coord.hyperhive_flake);
+    if let Some(ref rev) = current_rev {
+        let stored = std::fs::read_to_string(crate::auto_update::rev_marker_path(name)).ok();
+        if stored.as_deref() != Some(rev.as_str()) {
+            tracing::info!(%agent, %name, "start: rev stale — enqueuing rebuild");
+            coord.rebuild_queue.enqueue(
+                crate::rebuild_queue::QueueKind::Rebuild,
+                name.to_owned(),
+                crate::rebuild_queue::QueueSource::Manual,
+                format!("start {name}: rev stale — rebuilding first"),
+                None,
+            );
+            coord.emit_rebuild_queue_snapshot();
+            return AgentResponse::Ok;
+        }
+    }
     match crate::lifecycle::start(name).await {
         Ok(()) => {
             coord.kick_agent(name, "container started");