feat(ecc): prune plugin 43→12 items, promote 7 rules to .claude/rules/ (#245)

ECC community plugin pruning: removed 530+ non-essential files
(.cursor/, .opencode/, docs/ja-JP, docs/zh-CN, docs/zh-TW,
language-specific skills/agents/rules). Retained 4 agents,
3 commands, 5 skills. Promoted 13 rule files (8 common + 5
typescript) to .claude/rules/ for CC native loading. Extracted
reusable patterns to EXTRACTED-PATTERNS.md.

docs/zh-CN/rules/python/security.md

@@ -1,25 +0,0 @@
-# Python 安全
-
-> 本文档基于 [通用安全指南](../common/security.md) 扩展，补充了 Python 相关的内容。
-
-## 密钥管理
-
-```python
-import os
-from dotenv import load_dotenv
-
-load_dotenv()
-
-api_key = os.environ["OPENAI_API_KEY"]  # Raises KeyError if missing
-```
-
-## 安全扫描
-
-* 使用 **bandit** 进行静态安全分析：
-  ```bash
-  bandit -r src/
-  ```
-
-## 参考
-
-查看技能：`django-security` 以获取 Django 特定的安全指南（如适用）。