chore: apply ruff auto-fixes and remove dead AST scripts

ai_client.py

@@ -21,7 +21,6 @@ import hashlib
 import difflib
 import threading
 import requests
-from pathlib import Path
 from typing import Optional, Callable, Any
 import os
 import project_manager
@@ -1416,7 +1415,7 @@ def _send_anthropic(md_content: str, user_message: str, base_dir: str, file_item
 def _ensure_deepseek_client() -> None:
  global _deepseek_client
  if _deepseek_client is None:
-  creds = _load_credentials()
+  _load_credentials()
   # Placeholder for Dedicated DeepSeek SDK instantiation
   # import deepseek
   # _deepseek_client = deepseek.DeepSeek(api_key=creds["deepseek"]["api_key"])
@@ -1672,7 +1671,6 @@ def run_tier4_analysis(stderr: str) -> str:
   return f"[QA ANALYSIS FAILED] {e}"
   # ------------------------------------------------------------------ unified send
 
-import json
 
 
 def send(
@@ -1737,7 +1735,7 @@ def get_history_bleed_stats(md_content: str | None = None) -> dict[str, Any]:
  # For Anthropic, we have a robust estimator
   with _anthropic_history_lock:
    history_snapshot = list(_anthropic_history)
-  hist_only = _estimate_prompt_tokens([], history_snapshot) - 2500  # subtract fixed tools
+  _estimate_prompt_tokens([], history_snapshot) - 2500  # subtract fixed tools
   sys_tok = max(1, int(len(md_content) / _CHARS_PER_TOKEN)) if md_content else 0
   current_tokens = _estimate_prompt_tokens([], history_snapshot)
   if md_content:
@@ -1784,7 +1782,7 @@ def get_history_bleed_stats(md_content: str | None = None) -> dict[str, Any]:
      "current": current_tokens,
      "percentage": percentage,
     }, sys_tok=0, tool_tok=0)
-   except Exception as e:
+   except Exception:
     pass
   elif md_content:
    try:
@@ -1801,7 +1799,7 @@ def get_history_bleed_stats(md_content: str | None = None) -> dict[str, Any]:
      "current": current_tokens,
      "percentage": percentage,
     })
-   except Exception as e:
+   except Exception:
     pass
   return _add_bleed_derived({
    "provider": "gemini",