fix(aibox): never persist SOCKS5 proxy password to disk (F1/N1, +N11)

- config.set_proxy gains password_env (aligned with api_key_env
  convention): config file persists only the env var name; plaintext
  password lives in memory for the current session only
- _save_config deep-copies and nulls proxy.socks5.password before
  json.dump, so every save path is sanitized (defense in depth)
- get_proxy resolves password as in-memory plaintext first, then via
  password_env from os.environ; downstream consumers (llm_client,
  web tool curl args) unchanged
- legacy migration on load: plaintext found on disk is kept in memory
  for the session, file is immediately rewritten sanitized
- SetProxyTool exposes password_env and reports password source
- registry debug logs mask password/api_key/token/secret/authorization
  kwargs (N11)

Tests: new tests/test_config.py (3 cases: no plaintext on save,
password_env resolution, legacy migration); full suite 267 passed.
Audit report updated with Batch F progress.

aibox/tools/registry.py

@@ -15,6 +15,17 @@ from common import Logger, i18n
 
 from .base import Tool
 
+# 工具参数名命中这些关键词时，debug 日志里打码（防密码/密钥进日志文件）
+_SENSITIVE_PARAM_KEYS = {"password", "api_key", "token", "secret", "authorization"}
+
+
+def _sanitize_kwargs(kwargs: Dict) -> Dict:
+    """复制一份参数并把敏感键的值替换为 ***（仅用于日志输出）"""
+    return {
+        k: ("***" if str(k).lower() in _SENSITIVE_PARAM_KEYS else v)
+        for k, v in kwargs.items()
+    }
+
 
 class ToolRegistry:
     """工具注册器 - 支持技能热重载"""
@@ -63,7 +74,7 @@ class ToolRegistry:
         if not tool:
             return f"❌ 错误：找不到工具 '{name}'"
         
-        self.logger.debug(f"工具调用: {name}({kwargs})")
+        self.logger.debug(f"工具调用: {name}({_sanitize_kwargs(kwargs)})")
         start_time = time.time()
         
         try: