feat(FN-3773): default non-ephemeral agents to active and add polling task

Non-ephemeral agents now default to `active` state on creation (FN-3773), with aligned test coverage across the agent store and dashboard routes. The even-realities plugin gains a polling notification system including a notification store, card rendering, diff logic, and API routes. Review state per

Fusion-Task-Id: FN-3773

packages/dashboard/src/__tests__/routes-agents.test.ts

@@ -2113,6 +2113,11 @@ describe("Agent create/update routes", () => {
   });
 
   it("POST /api/agents/:id/state returns 400 for invalid state transitions", async () => {
+    const { AgentStore } = await import("@fusion/core");
+    const agentStore = new AgentStore({ rootDir: fusionDir });
+    await agentStore.init();
+    await agentStore.updateAgentState(agentId, "idle");
+
     const res = await REQUEST(
       buildAgentApp(),
       "POST",