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/file_tools.py

@@ -4,9 +4,7 @@
 import errno
 import json
 import logging
-import os
 import threading
-from typing import Optional
 from tools.file_operations import ShellFileOperations
 from agent.redact import redact_sensitive_text
 
@@ -50,8 +48,8 @@ def _get_file_ops(task_id: str = "default") -> ShellFileOperations:
     from tools.terminal_tool import (
         _active_environments, _env_lock, _create_environment,
         _get_env_config, _last_activity, _start_cleanup_thread,
-        _check_disk_usage_warning,
-        _creation_locks, _creation_locks_lock,
+        _creation_locks,
+        _creation_locks_lock,
     )
     import time