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Superseded wrappers (replaced by newer implementations):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- hermes_cli/callbacks.py: sudo_password_callback (superseded by CLI method)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- tools/file_tools.py: get_file_tools (superseded by registry.register)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/tools_config.py

@@ -61,22 +61,6 @@ def _prompt(question: str, default: str = None, password: bool = False) -> str:
         print()
         return default or ""
 
-def _prompt_yes_no(question: str, default: bool = True) -> bool:
-    default_str = "Y/n" if default else "y/N"
-    while True:
-        try:
-            value = input(color(f"{question} [{default_str}]: ", Colors.YELLOW)).strip().lower()
-        except (KeyboardInterrupt, EOFError):
-            print()
-            return default
-        if not value:
-            return default
-        if value in ('y', 'yes'):
-            return True
-        if value in ('n', 'no'):
-            return False
-
-
 # ─── Toolset Registry ─────────────────────────────────────────────────────────
 
 # Toolsets shown in the configurator, grouped for display.