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/process_registry.py

@@ -34,7 +34,6 @@ import logging
 import os
 import platform
 import shlex
-import shutil
 import signal
 import subprocess
 import threading
@@ -44,7 +43,6 @@ import uuid
 _IS_WINDOWS = platform.system() == "Windows"
 from tools.environments.local import _find_shell, _sanitize_subprocess_env
 from dataclasses import dataclass, field
-from pathlib import Path
 from typing import Any, Dict, List, Optional
 
 from hermes_cli.config import get_hermes_home