feat: add Python/Django support and enhance READMEs (#139)

## Python Support
- **agents/python-reviewer.md**: Expert Python code review agent with PEP 8 compliance, type hints, security, and performance checks
- **commands/python-review.md**: Slash command for automated Python code review with ruff, mypy, pylint, black, bandit
- **skills/python-patterns/SKILL.md**: Python idioms, type hints, error handling, context managers, decorators, concurrency
- **skills/python-testing/SKILL.md**: pytest configuration, fixtures, parametrization, mocking, async testing, TDD methodology

## Django Support
- **skills/django-patterns/SKILL.md**: Django architecture, DRF patterns, project structure, QuerySets, serializers, ViewSets, service layer, caching
- **skills/django-security/SKILL.md**: Django security best practices, authentication, CSRF, SQL injection, XSS prevention, production settings
- **skills/django-tdd/SKILL.md**: Django testing with pytest-django, Factory Boy, model testing, API testing, integration testing
- **skills/django-verification/SKILL.md**: Pre-deployment verification loop including migrations, tests, security scans, performance checks

## Documentation Enhancements
- **Quick Start**: Added 3-step quick start guide to all READMEs (EN, zh-CN, zh-TW)
- **Beautification**: Added emoji icons for better visual hierarchy across all READMEs
- **.claude-plugin/plugin.json**: Added python-reviewer to agents list

All files follow project conventions with proper frontmatter, markdown formatting, and comprehensive code examples.

Co-authored-by: Freakz3z <freakk@FreakkdeMacBook-Air.local>
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

.claude-plugin/plugin.json

@@ -33,6 +33,7 @@
     "./agents/go-build-resolver.md",
     "./agents/go-reviewer.md",
     "./agents/planner.md",
+    "./agents/python-reviewer.md",
     "./agents/refactor-cleaner.md",
     "./agents/security-reviewer.md",
     "./agents/tdd-guide.md"