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

plugins/google_meet/cli.py

@@ -13,7 +13,6 @@ from __future__ import annotations
 
 import argparse
 import json
-import os
 import sys
 from pathlib import Path
 from typing import Optional

plugins/platforms/irc/adapter.py

@@ -49,8 +49,7 @@ from gateway.platforms.base import (
     MessageEvent,
     MessageType,
 )
-from gateway.session import SessionSource
-from gateway.config import PlatformConfig, Platform
+from gateway.config import Platform
 
 
 # ---------------------------------------------------------------------------

plugins/platforms/line/adapter.py

@@ -76,7 +76,7 @@ import time
 import uuid
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import Any, Awaitable, Callable, Dict, List, Optional, Set, Tuple
+from typing import Any, Dict, List, Optional, Set, Tuple
 from urllib.parse import quote as _urlquote
 
 logger = logging.getLogger(__name__)
@@ -95,7 +95,6 @@ from gateway.platforms.base import (
     cache_image_from_bytes,
 )
 from gateway.config import Platform
-from gateway.session import SessionSource
 
 
 # ---------------------------------------------------------------------------

plugins/spotify/tools.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from typing import Any, Dict, List
+from typing import Any, List
 
 from hermes_cli.auth import get_auth_status
 from plugins.spotify.client import (

plugins/teams_pipeline/cli.py

@@ -24,7 +24,6 @@ from plugins.teams_pipeline.store import TeamsPipelineStore, resolve_teams_pipel
 from plugins.teams_pipeline.subscriptions import (
     build_graph_client,
     maintain_graph_subscriptions,
-    sync_graph_subscription_record,
 )
 from tools.microsoft_graph_auth import MicrosoftGraphConfigError, MicrosoftGraphTokenProvider
 

plugins/teams_pipeline/pipeline.py

@@ -7,7 +7,6 @@ import json
 import logging
 import os
 import shutil
-import subprocess
 import tempfile
 import uuid
 from dataclasses import dataclass
@@ -19,7 +18,6 @@ import httpx
 from agent.auxiliary_client import async_call_llm, extract_content_or_reasoning
 from hermes_constants import get_hermes_home
 from plugins.teams_pipeline.meetings import (
-    TeamsMeetingArtifactNotFoundError,
     download_recording_artifact,
     enrich_meeting_with_call_record,
     fetch_preferred_transcript_text,