chore: remove ~100 unused imports across 55 files (#3016)

Automated cleanup via pyflakes + autoflake with manual review.

Changes:
- Removed unused stdlib imports (os, sys, json, pathlib.Path, etc.)
- Removed unused typing imports (List, Dict, Any, Optional, Tuple, Set, etc.)
- Removed unused internal imports (hermes_cli.auth, hermes_cli.config, etc.)
- Fixed cli.py: removed 8 shadowed banner imports (imported from hermes_cli.banner
  then immediately redefined locally — only build_welcome_banner is actually used)
- Added noqa comments to imports that appear unused but serve a purpose:
  - Re-exports (gateway/session.py SessionResetPolicy, tools/terminal_tool.py
    is_interrupted/_interrupt_event)
  - SDK presence checks in try/except (daytona, fal_client, discord)
  - Test mock targets (auxiliary_client.py Path, mcp_config.py get_hermes_home)

Zero behavioral changes. Full test suite passes (6162/6162, 2 pre-existing
streaming test failures unrelated to this change).

acp_adapter/events.py

@@ -10,7 +10,7 @@ thread while the event loop lives on the main thread).
 import asyncio
 import json
 import logging
-from collections import defaultdict, deque
+from collections import deque
 from typing import Any, Callable, Deque, Dict
 
 import acp

acp_adapter/permissions.py

@@ -5,14 +5,11 @@ from __future__ import annotations
 import asyncio
 import logging
 from concurrent.futures import TimeoutError as FutureTimeout
-from typing import Any, Callable, Optional
+from typing import Callable
 
 from acp.schema import (
     AllowedOutcome,
-    DeniedOutcome,
     PermissionOption,
-    RequestPermissionRequest,
-    SelectedPermissionOutcome,
 )
 
 logger = logging.getLogger(__name__)