feat(frontend): agent activity dropdown (#10416)

## Changes 🏗️


https://github.com/user-attachments/assets/42e1c896-5f3b-447c-aee9-4f5963c217d9

There is now a 🔔 icon on the Navigation bar that shows previous agent
runs and displays real-time agent running status.

If you run an agent, the bell will show on a badge how many agents are
running. If you hover over it, a hint appears. If you click on it, it
opens a dropdown and displays the executions with their status ( _which
should match what we have in library functionality, not design-wise_ ).

I leveraged the existing APIs for this purpose. Most of the run logic is
[encapsulated on this
hook](https://github.com/Significant-Gravitas/AutoGPT/compare/dev...feat/agent-notifications?expand=1#diff-a9e7f2904d6283b094aca19b64c7168e8c66be1d5e0bb454be8978cb98526617)
and is also an independent `<AgentActivityDropdown />` component.

Clicking on an agent run opens that run in the library page.

This new functionality is covered by E2E tests 💆🏽 ✔️ 

## Checklist 📋

### For code changes:
- [x] I have clearly listed my changes in the PR description
- [x] I have made a test plan
- [x] I have tested my changes according to the test plan:
  - [x] The navigation bar layout looks good when logged out
  - [x] The navigation bar layout looks good when logged in
  - [x] Open an agent in the library and click `Run`
- [x] See the real-time activity of the agent running on the navigation
bar bell icon

### For configuration changes:

_No configuration changes needed._

autogpt_platform/frontend/package.json

@@ -75,6 +75,7 @@
     "moment": "2.30.1",
     "next": "15.3.5",
     "next-themes": "0.4.6",
+    "nuqs": "2.4.3",
     "party-js": "2.2.0",
     "react": "18.3.1",
     "react-day-picker": "9.8.0",