chore: prune unused imports and duplicate import redefinitions

Remove unused imports (F401) and duplicate/shadowed import
redefinitions (F811) across the codebase using ruff's safe
autofixes. No behavioral changes -- imports only.

- ~1400 safe autofixes applied across 644 files (net -1072 lines)
- __init__.py re-exports preserved (excluded from F401 removal so
  public re-export surfaces stay intact)
- Re-exports that are imported or monkeypatched by tests but look
  unused in their defining module are kept with explicit # noqa:
  F401 (gateway/run.py load_dotenv; run_agent re-exports from
  agent.message_sanitization, agent.context_compressor,
  agent.retry_utils, agent.prompt_builder, agent.process_bootstrap,
  agent.codex_responses_adapter)
- Unsafe F841 (unused-variable) fixes deliberately skipped -- those
  can change behavior when the RHS has side effects
- ruff lints remain disabled in pyproject.toml (only PLW1514 is
  selected); this is a one-time cleanup, not a config change

Verification:
- python -m compileall: clean
- pytest --collect-only: all 27161 tests collect (zero import errors)
- core entry points import clean (run_agent, model_tools, cli,
  toolsets, hermes_state, batch_runner, gateway)
- static scan: every name any test imports directly from an edited
  module still resolves

run_agent.py

@@ -33,26 +33,19 @@ except ModuleNotFoundError:
 
 import asyncio
 import base64
-import concurrent.futures
-import contextvars
 import copy
 import hashlib
 import json
 import logging
 logger = logging.getLogger(__name__)
 import os
-import random
 import re
-import ssl
 import sys
 import tempfile
 import time
 import threading
-from types import SimpleNamespace
-import urllib.request
 import uuid
 from typing import List, Dict, Any, Optional
-from urllib.parse import urlparse, parse_qs, urlunparse
 # NOTE: `from openai import OpenAI` is deliberately NOT at module top — the
 # SDK pulls ~240 ms of imports. We expose `OpenAI` as a thin proxy object
 # that imports the SDK on first call/isinstance check. This preserves:
@@ -73,12 +66,6 @@ from hermes_constants import get_hermes_home
 # OpenAI lazy proxy + safe stdio + proxy URL helpers — see agent/process_bootstrap.py.
 # `OpenAI` is re-exported here so `patch("run_agent.OpenAI", ...)` in tests works.
 from agent.process_bootstrap import (
-    OpenAI,
-    _OpenAIProxy,
-    _load_openai_cls,
-    _SafeWriter,
-    _install_safe_stdio,
-    _get_proxy_from_env,
     _get_proxy_for_base_url,
 )
 from agent.iteration_budget import IterationBudget
@@ -102,77 +89,27 @@ else:
 
 # Import our tool system
 from model_tools import (
-    get_tool_definitions,
     get_toolset_for_tool,
-    handle_function_call,
-    check_toolset_requirements,
 )
-from tools.terminal_tool import cleanup_vm, get_active_env, is_persistent_env
-from tools.terminal_tool import (
-    set_approval_callback as _set_approval_callback,
-    set_sudo_password_callback as _set_sudo_password_callback,
-    _get_approval_callback,
-    _get_sudo_password_callback,
-)
-from tools.tool_result_storage import maybe_persist_tool_result, enforce_turn_budget
+from tools.terminal_tool import cleanup_vm
 from tools.interrupt import set_interrupt as _set_interrupt
 from tools.browser_tool import cleanup_browser
 
 
 # Agent internals extracted to agent/ package for modularity
-from agent.memory_manager import StreamingContextScrubber, build_memory_context_block, sanitize_context
-from agent.think_scrubber import StreamingThinkScrubber
-from agent.retry_utils import jittered_backoff
-from agent.error_classifier import classify_api_error, FailoverReason
+from agent.memory_manager import sanitize_context
+from agent.error_classifier import FailoverReason
 from agent.redact import redact_sensitive_text
-from agent.prompt_builder import (
-    DEFAULT_AGENT_IDENTITY, PLATFORM_HINTS,
-    MEMORY_GUIDANCE, SESSION_SEARCH_GUIDANCE, SKILLS_GUIDANCE,
-    HERMES_AGENT_HELP_GUIDANCE,
-    KANBAN_GUIDANCE,
-    build_nous_subscription_prompt,
-)
 from agent.model_metadata import (
-    fetch_model_metadata,
-    estimate_tokens_rough, estimate_messages_tokens_rough, estimate_request_tokens_rough,
-    get_next_probe_tier, parse_context_limit_from_error,
-    parse_available_output_tokens_from_error,
-    save_context_length, is_local_endpoint,
-    query_ollama_num_ctx,
+    is_local_endpoint,
 )
-from agent.context_compressor import ContextCompressor
-from agent.subdirectory_hints import SubdirectoryHintTracker
-from agent.prompt_caching import apply_anthropic_cache_control
-from agent.prompt_builder import build_skills_system_prompt, build_context_files_prompt, build_environment_hints, load_soul_md, TOOL_USE_ENFORCEMENT_GUIDANCE, TOOL_USE_ENFORCEMENT_MODELS, GOOGLE_MODEL_OPERATIONAL_GUIDANCE, OPENAI_MODEL_EXECUTION_GUIDANCE
-from agent.usage_pricing import estimate_usage_cost, normalize_usage
-from agent.codex_responses_adapter import (
-    _derive_responses_function_call_id as _codex_derive_responses_function_call_id,
-    _deterministic_call_id as _codex_deterministic_call_id,
-    _split_responses_tool_id as _codex_split_responses_tool_id,
-    _summarize_user_message_for_log,
-)
-from agent.display import (
-    KawaiiSpinner, build_tool_preview as _build_tool_preview,
-    get_cute_tool_message as _get_cute_tool_message_impl,
-    _detect_tool_failure,
-    get_tool_emoji as _get_tool_emoji,
-)
-from agent.tool_guardrails import (
-    ToolCallGuardrailConfig,
-    ToolCallGuardrailController,
-    ToolGuardrailDecision,
-    append_toolguard_guidance,
-    toolguard_synthetic_result,
-)
-from agent.tool_result_classification import (
-    FILE_MUTATING_TOOL_NAMES as _FILE_MUTATING_TOOLS,
-    file_mutation_result_landed,
-)
-from agent.trajectory import (
-    convert_scratchpad_to_think,
-    save_trajectory as _save_trajectory_to_file,
-)
-from agent.message_sanitization import (
+from agent.usage_pricing import normalize_usage
+# Re-exported for tests that monkeypatch these symbols on run_agent.
+from agent.context_compressor import ContextCompressor  # noqa: F401
+from agent.retry_utils import jittered_backoff  # noqa: F401
+from agent.prompt_builder import build_skills_system_prompt, load_soul_md  # noqa: F401
+from agent.process_bootstrap import _get_proxy_from_env  # noqa: F401
+from agent.message_sanitization import (  # noqa: F401
     _SURROGATE_RE,
     _sanitize_surrogates,
     _sanitize_structure_surrogates,
@@ -185,25 +122,33 @@ from agent.message_sanitization import (
     _strip_images_from_messages,
     _sanitize_structure_non_ascii,
 )
+from agent.codex_responses_adapter import (
+    _derive_responses_function_call_id as _codex_derive_responses_function_call_id,
+    _deterministic_call_id as _codex_deterministic_call_id,
+    _split_responses_tool_id as _codex_split_responses_tool_id,
+    _summarize_user_message_for_log,  # noqa: F401  # re-exported for tests
+)
+from agent.tool_guardrails import (
+    ToolGuardrailDecision,
+    append_toolguard_guidance,
+    toolguard_synthetic_result,
+)
+from agent.tool_result_classification import (
+    FILE_MUTATING_TOOL_NAMES as _FILE_MUTATING_TOOLS,
+    file_mutation_result_landed,
+)
+from agent.trajectory import (
+    convert_scratchpad_to_think,
+    save_trajectory as _save_trajectory_to_file,
+)
 from agent.tool_dispatch_helpers import (
-    _NEVER_PARALLEL_TOOLS,
-    _PARALLEL_SAFE_TOOLS,
-    _PATH_SCOPED_TOOLS,
-    _DESTRUCTIVE_PATTERNS,
-    _REDIRECT_OVERWRITE,
-    _is_destructive_command,
     _should_parallelize_tool_batch,
-    _extract_parallel_scope_path,
-    _paths_overlap,
     _is_multimodal_tool_result,
     _multimodal_text_summary,
-    _append_subdir_hint_to_multimodal,
     _extract_file_mutation_targets,
     _extract_error_preview,
-    _trajectory_normalize_msg,
 )
-from utils import atomic_json_write, base_url_host_matches, base_url_hostname, env_var_enabled, normalize_proxy_url
-from hermes_cli.config import cfg_get
+from utils import atomic_json_write, base_url_host_matches, base_url_hostname