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).

hermes_cli/banner.py

@@ -11,7 +11,7 @@ import subprocess
 import threading
 import time
 from pathlib import Path
-from typing import Dict, List, Any, Optional
+from typing import Dict, List, Optional
 
 from rich.console import Console
 from rich.panel import Panel
@@ -257,7 +257,7 @@ def build_welcome_banner(console: Console, model: str, cwd: str,
         get_toolset_for_tool: Callable to map tool name -> toolset name.
         context_length: Model's context window size in tokens.
     """
-    from model_tools import check_tool_availability, TOOLSET_REQUIREMENTS
+    from model_tools import check_tool_availability
     if get_toolset_for_tool is None:
         from model_tools import get_toolset_for_tool