feat: add unified switch.py for cross-platform skill porting

Single script to copy skills between AI platforms (Cursor, Codex,
Copilot, Gemini CLI, OpenCode) with path rewriting and optional
runtime switching. Includes interactive mode for newcomers.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/switch-to-python.py

@@ -5,6 +5,7 @@
 import os, re, glob, sys
 
 def main():
+    print("Совет: используйте 'python scripts/switch.py --runtime python' (новый интерфейс)\n")
     repo_root = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
     skills_dir = os.path.join(repo_root, '.claude', 'skills')