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).

tools/voice_mode.py

@@ -19,7 +19,6 @@ import tempfile
 import threading
 import time
 import wave
-from pathlib import Path
 from typing import Any, Dict, List, Optional
 
 logger = logging.getLogger(__name__)
@@ -710,7 +709,7 @@ def check_voice_requirements() -> Dict[str, Any]:
         ``missing_packages``, and ``details``.
     """
     # Determine STT provider availability
-    from tools.transcription_tools import _get_provider, _load_stt_config, is_stt_enabled, _HAS_FASTER_WHISPER
+    from tools.transcription_tools import _get_provider, _load_stt_config, is_stt_enabled
     stt_config = _load_stt_config()
     stt_enabled = is_stt_enabled(stt_config)
     stt_provider = _get_provider(stt_config)