fix: pause routines whose assigned agent is deleted

Unassigning alone left an active routine that could never dispatch.
assertRoutineCanEnable already treats active-with-no-assignee as invalid, so the
teardown was creating a state the service itself refuses to construct. Pause the
routine as well, so the condition is visible instead of silent.

Author: markkuhr

server/src/services/agents.ts

@@ -747,7 +747,14 @@ export function agentService(db: Db) {
           .update(issues)
           .set({ assigneeAgentId: null, createdByAgentId: null })
           .where(or(eq(issues.assigneeAgentId, id), eq(issues.createdByAgentId, id)));
-        await tx.update(routines).set({ assigneeAgentId: null }).where(eq(routines.assigneeAgentId, id));
+        // Pause as well as unassign. assertRoutineCanEnable already treats an
+        // active routine with no assignee as invalid, so leaving it active would
+        // create a state the service itself refuses to construct, and the routine
+        // would silently never dispatch.
+        await tx
+          .update(routines)
+          .set({ assigneeAgentId: null, status: "paused" })
+          .where(eq(routines.assigneeAgentId, id));
         await tx.delete(heartbeatRunEvents).where(eq(heartbeatRunEvents.agentId, id));
         await tx.delete(agentTaskSessions).where(eq(agentTaskSessions.agentId, id));
         await tx.delete(activityLog).where(