refactor: remove 24 confirmed dead functions — 432 lines of unused code

Each function was verified to have exactly 1 reference in the entire
codebase (its own definition). Zero calls, zero imports, zero string
references anywhere including tests.

Removed by category:

Superseded wrappers (replaced by newer implementations):
- agent/anthropic_adapter.py: run_hermes_oauth_login, refresh_hermes_oauth_token
- hermes_cli/callbacks.py: sudo_password_callback (superseded by CLI method)
- hermes_cli/setup.py: _set_model_provider, _sync_model_from_disk
- tools/file_tools.py: get_file_tools (superseded by registry.register)
- tools/cronjob_tools.py: get_cronjob_tool_definitions (same)
- tools/terminal_tool.py: _check_dangerous_command (_check_all_guards used)

Dead private helpers (lost their callers during refactors):
- agent/anthropic_adapter.py: _convert_user_content_part_to_anthropic
- agent/display.py: honcho_session_line, write_tty
- hermes_cli/providers.py: _build_labels (+ dead _labels_cache var)
- hermes_cli/tools_config.py: _prompt_yes_no
- hermes_cli/models.py: _extract_model_ids
- hermes_cli/uninstall.py: log_error
- gateway/platforms/feishu.py: _is_loop_ready
- tools/file_operations.py: _read_image (64-line method)
- tools/process_registry.py: cleanup_expired
- tools/skill_manager_tool.py: check_skill_manage_requirements

Dead class methods (zero callers):
- run_agent.py: _is_anthropic_url (logic duplicated inline at L618)
- run_agent.py: _classify_empty_content_response (68-line method, never wired)
- cli.py: reset_conversation (callers all use new_session directly)
- cli.py: _clear_current_input (added but never wired in)

Other:
- gateway/delivery.py: build_delivery_context_for_tool
- tools/browser_tool.py: get_active_browser_sessions

hermes_cli/providers.py

@@ -344,18 +344,6 @@ def get_label(provider_id: str) -> str:
     return canonical
 
 
-# Build LABELS dict for backward compat
-def _build_labels() -> Dict[str, str]:
-    """Build labels dict from overlays + overrides. Lazy, cached."""
-    labels: Dict[str, str] = {}
-    for pid in HERMES_OVERLAYS:
-        labels[pid] = get_label(pid)
-    labels.update(_LABEL_OVERRIDES)
-    return labels
-
-# Lazy-built on first access
-_labels_cache: Optional[Dict[str, str]] = None
-
 # For direct import compat, expose as module-level dict
 # Built on demand by get_label() calls
 LABELS: Dict[str, str] = {