chore: prune unused imports and duplicate import redefinitions

Remove unused imports (F401) and duplicate/shadowed import
redefinitions (F811) across the codebase using ruff's safe
autofixes. No behavioral changes -- imports only.

- ~1400 safe autofixes applied across 644 files (net -1072 lines)
- __init__.py re-exports preserved (excluded from F401 removal so
  public re-export surfaces stay intact)
- Re-exports that are imported or monkeypatched by tests but look
  unused in their defining module are kept with explicit # noqa:
  F401 (gateway/run.py load_dotenv; run_agent re-exports from
  agent.message_sanitization, agent.context_compressor,
  agent.retry_utils, agent.prompt_builder, agent.process_bootstrap,
  agent.codex_responses_adapter)
- Unsafe F841 (unused-variable) fixes deliberately skipped -- those
  can change behavior when the RHS has side effects
- ruff lints remain disabled in pyproject.toml (only PLW1514 is
  selected); this is a one-time cleanup, not a config change

Verification:
- python -m compileall: clean
- pytest --collect-only: all 27161 tests collect (zero import errors)
- core entry points import clean (run_agent, model_tools, cli,
  toolsets, hermes_state, batch_runner, gateway)
- static scan: every name any test imports directly from an edited
  module still resolves

tests/plugins/image_gen/test_fal_provider.py

@@ -16,7 +16,6 @@ from __future__ import annotations
 import json
 from unittest.mock import MagicMock
 
-import pytest
 
 
 # ---------------------------------------------------------------------------

tests/plugins/image_gen/test_openai_provider.py

@@ -137,7 +137,6 @@ class TestGenerate:
         assert result["error_type"] == "auth_required"
 
     def test_b64_saves_to_cache(self, provider, tmp_path):
-        import base64
         png_bytes = bytes.fromhex(_PNG_HEX)
         fake_client = MagicMock()
         fake_client.images.generate.return_value = _fake_response(b64=_b64_png())

tests/plugins/image_gen/test_xai_provider.py

@@ -4,7 +4,6 @@
 from __future__ import annotations
 
 import json
-import os
 from pathlib import Path
 from unittest.mock import MagicMock, patch
 

tests/plugins/memory/test_hindsight_provider.py

@@ -1016,7 +1016,6 @@ class TestSessionSwitchBufferFlush:
         old session to settle before clearing _prefetch_result, otherwise
         the thread can race and re-populate the field after the clear."""
         import threading
-        import time as _time
 
         gate = threading.Event()
         finished = threading.Event()

tests/plugins/memory/test_mem0_v2.py

@@ -4,7 +4,6 @@ Salvaged from PRs #5301 (qaqcvc) and #5117 (vvvanguards).
 """
 
 import json
-import pytest
 
 from plugins.memory.mem0 import Mem0MemoryProvider
 

tests/plugins/test_google_meet_audio.py

@@ -6,7 +6,6 @@ without actually invoking those tools on the host.
 
 from __future__ import annotations
 
-import subprocess
 from unittest.mock import MagicMock, patch
 
 import pytest

tests/plugins/test_google_meet_node.py

@@ -12,7 +12,6 @@ import argparse
 import asyncio
 import json
 from pathlib import Path
-from unittest.mock import MagicMock, patch
 
 import pytest
 

tests/plugins/test_google_meet_plugin.py

@@ -764,7 +764,6 @@ def test_cmd_install_refuses_windows(capsys):
 def test_cmd_install_runs_pip_and_playwright(capsys):
     """End-to-end wiring: pip + playwright install invoked, returncodes handled."""
     from plugins.google_meet.cli import _cmd_install
-    import subprocess as _sp
 
     calls = []
     class _FakeRes:

tests/plugins/test_google_meet_realtime.py

@@ -8,10 +8,7 @@ from __future__ import annotations
 import base64
 import json
 import sys
-import threading
 import types
-from pathlib import Path
-from unittest.mock import patch
 
 import pytest
 

tests/plugins/test_kanban_dashboard_plugin.py

@@ -835,8 +835,6 @@ def test_ws_events_swallows_cancellation_on_shutdown(tmp_path, monkeypatch):
     the cancellation outcome deterministically.
     """
     import asyncio
-    import types
-    import sys as _sys
 
     home = tmp_path / ".hermes"
     home.mkdir()

tests/plugins/test_kanban_worker_runs.py

@@ -13,7 +13,7 @@ import secrets
 import sys
 import time
 from pathlib import Path
-from unittest.mock import MagicMock, patch
+from unittest.mock import MagicMock
 
 import pytest
 from fastapi import FastAPI

tests/plugins/test_retaindb_plugin.py

@@ -5,13 +5,10 @@ RetainDBMemoryProvider lifecycle/tools/prefetch, thread management, connection p
 """
 
 import json
-import os
 import sqlite3
-import tempfile
-import threading
 import time
 from pathlib import Path
-from unittest.mock import MagicMock, patch, PropertyMock
+from unittest.mock import MagicMock, patch
 
 import pytest
 
@@ -67,8 +64,6 @@ from plugins.memory.retaindb import (
     _WriteQueue,
     _build_overlay,
     RetainDBMemoryProvider,
-    _ASYNC_SHUTDOWN,
-    _DEFAULT_BASE_URL,
 )
 
 

tests/plugins/test_security_guidance_plugin.py

@@ -16,9 +16,7 @@ Covers ``plugins/security-guidance/``:
   * Bundled-plugin discovery via ``PluginManager.discover_and_load``.
 """
 
-import importlib
 import importlib.util
-import json
 import sys
 import types
 from pathlib import Path

tests/plugins/test_teams_pipeline_plugin.py

@@ -5,7 +5,6 @@ from __future__ import annotations
 import asyncio
 from types import SimpleNamespace
 from pathlib import Path
-from unittest.mock import MagicMock
 
 import pytest
 

tests/plugins/web/test_web_search_provider_plugins.py

@@ -20,9 +20,6 @@ from __future__ import annotations
 
 import asyncio
 import inspect
-import os
-import sys
-from typing import Any, Dict, List
 
 import pytest
 
@@ -268,7 +265,7 @@ class TestRegistryResolution:
         surfaces a precise "FOO_API_KEY is not set" error instead.
         """
         _ensure_plugins_loaded()
-        from agent.web_search_registry import _resolve, get_provider
+        from agent.web_search_registry import _resolve
 
         # No BRAVE_SEARCH_API_KEY (fixture cleared it).
         result = _resolve("brave-free", capability="search")