herdr phase 1c: wizard runtime picker + on_launch auto-dispatch

Closes the operator loop for the second-runtime path. Missions
created with runtime='local_herdr' now spawn a Herdr pane on their
target_node automatically on draft→running.

Frontend (MissionWizard):
  - Step 4 grows a "Runtime" section above Schedule
  - Radio: "Hosted (ZeroClaw)" default | "On a fleet node (Herdr)"
  - Local-Herdr shows a dropdown of ONLINE nodes only (from
    /api/nodes filtered by status='online')
  - canNext blocks Next when local_herdr picked without a node
  - Review step shows "Runtime: Herdr on <node-name>" or "Hosted"
  - Empty-online-nodes state hints "Connect one from INFRA first"

Backend:
  - mission_orchestrator::on_launch grows a NodeHub param; when
    mission.runtime_kind='local_herdr' + target_node_id set +
    hub present → calls fleet_herdr::dispatch(). Non-fatal:
    logs and continues so a research_only mission with a Herdr
    runtime chosen accidentally still boots the team.
  - routes::missions::set_status passes state.node_hub through.
  - Test call sites updated to pass None for the new param
    (integration tests don't drive real fleet nodes).

CLI stub: on_launch currently hard-codes cli="claude" for the
Herdr pane. Phase 4 will read that from the team template so a
research team → kimi, gpu team → claude, etc.

Verified: cargo check --workspace + cargo test
-p cm-api --test mission_orchestrator + tsc --noEmit all green.

crates/cm-api/src/mission_orchestrator.rs

@@ -37,6 +37,7 @@ pub async fn on_launch(
     workspace_id: WorkspaceId,
     user_id: cm_domain::UserId,
     mission_id: Uuid,
+    node_hub: Option<std::sync::Arc<crate::fleet::NodeHub>>,
 ) -> Result<Option<Uuid>, String> {
     let Some(mission) = cm_db::repo::missions::get(pool, mission_id, workspace_id.as_uuid())
         .await
@@ -100,6 +101,38 @@ pub async fn on_launch(
         ),
     }
 
+    // Herdr second-runtime: if runtime_kind='local_herdr', spawn a
+    // pane on target_node running the first available local CLI.
+    // Non-fatal on failure — the operator sees the error in server
+    // logs and can manually retry via POST /herdr-dispatch.
+    if mission.runtime_kind == "local_herdr" {
+        if let (Some(hub), Some(node_id)) = (node_hub, mission.target_node_id) {
+            let prompt = mission.description.clone().unwrap_or_default();
+            let cli = "claude"; // TODO(phase-4): pick from team template
+            match crate::fleet_herdr::dispatch(
+                hub,
+                cm_domain::NodeId::from(node_id),
+                mission_id,
+                cli,
+                &prompt,
+            )
+            .await
+            {
+                Ok(handle) => eprintln!(
+                    "mission_orchestrator: herdr pane {} spawned on node {}",
+                    handle.pane_id, node_id
+                ),
+                Err(e) => eprintln!(
+                    "mission_orchestrator: herdr dispatch for {mission_id} failed (continuing): {e}"
+                ),
+            }
+        } else {
+            eprintln!(
+                "mission_orchestrator: mission {mission_id} is local_herdr but node_hub or target_node missing"
+            );
+        }
+    }
+
     Ok(Some(team_id))
 }