Fix merge conflict resolution artifacts in agents.rs

- Add missing closing brace for spawn_watchdog function
- Remove leftover <<<<<<< HEAD conflict marker in test module
- Restore conflict marker test data that was incorrectly stripped
- Add missing completed_at field in inject_test_agent_with_handle

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/agents.rs

@@ -1573,6 +1573,7 @@ impl AgentPool {
                 completion: None,
                 project_root: None,
                 log_session_id: None,
+                completed_at: None,
             },
         );
         tx
@@ -1601,6 +1602,8 @@ impl AgentPool {
                 check_orphaned_agents(&agents);
             }
         });
+    }
+
     /// Remove all agent entries for a given story_id from the pool.
     ///
     /// Called when a story is archived so that stale entries don't accumulate.
@@ -4796,6 +4799,7 @@ footer
     #[test]
     fn resolve_simple_conflicts_malformed_no_separator() {
         let input = "\
+<<<<<<< HEAD
 ours
 >>>>>>> feature
 ";
@@ -4806,7 +4810,9 @@ ours
     #[test]
     fn resolve_simple_conflicts_malformed_no_end() {
         let input = "\
+<<<<<<< HEAD
 ours
+=======
 theirs
 ";
         let result = resolve_simple_conflicts(input);
@@ -5082,7 +5088,6 @@ theirs
         assert!(report.had_conflicts, "should report conflicts");
     }
 
-<<<<<<< HEAD
     // ── process health monitoring tests ──────────────────────────────────────
 
     /// Demonstrates that the PTY read-loop inactivity timeout fires when no output