feat(server, builder): Implement "STOP" button for graph runs (#7892)

- feat(builder): Add "Stop Run" buttons to monitor and builder
  - Implement additional state management in `useAgentGraph` hook
    - Add "stop" request mechanism
    - Implement execution status tracking using WebSockets
    - Add `isSaving`, `isRunning`, `isStopping` outputs
    - Add `requestStopRun` method
      - Rename `requestSaveRun` to `requestSaveAndRun` for clarity
  - Add needed functionality for the above to `AutoGPTServerAPI` client
    - Add `stopGraphExecution` method
    - Add support for multiple handlers per WebSocket method
    - Fix parsing of timestamps in `execution_event` WebSocket messages
  - Add `IconSquare` from Lucide to `@/components/ui/icons`

- feat(server): Add `POST /graphs/{graph_id}/executions/{graph_exec_id}/stop` route
  - Add `stop_graph_run` method to `AgentServer`

- feat(server): Add `cancel_execution` method to `ExecutionManager`
  - Replace node executor `ProcessPoolExecutor` by `multiprocessing.Pool` (which has a `terminate()` method)
    - Remove now unnecessary `Executor.wait_future(..)` method
  - Add `get_graph_execution(..)` in `.data.execution`

- fix(server): Reduce number of node executors to 5 per graph executor
  This is necessary because `multiprocessing.Pool` spawns its workers on init, instead of based on demand like `ProcessPoolExecutor` does

- dx(server): Improve debug logging in `ExecutionManager`
- ci(server): Add debug logging mode to CI Pytest step

### Other improvements
Server:
- Improve output type of `ExecutionManager.add_execution(..)`
- Renamed a few things in `.server.rest_api` for consistency

Front end:
- Improved typing in `AutoGPTServerAPI` client

.github/workflows/autogpt-server-ci.yml

@@ -128,9 +128,14 @@ jobs:
 
       - name: Run pytest with coverage
         run: |
-          poetry run pytest -vv \
-            test
+          if [[ "${{ runner.debug }}" == "1" ]]; then
+            poetry run pytest -vv -o log_cli=true -o log_cli_level=DEBUG test
+          else
+            poetry run pytest -vv test
+          fi
         if: success() || (failure() && steps.lint.outcome == 'failure')
+        env:
+          LOG_LEVEL: ${{ runner.debug && 'DEBUG' || 'INFO' }}
     env:
       CI: true
       PLAIN_OUTPUT: True