fix(skills): remove phantom resource references and fix CoC links (#447)

Remove references to non-existent resource files (references/, assets/,
scripts/, examples/) from 115 skill SKILL.md files. These sections
pointed to directories and files that were never created, causing
confusion when users install skills.

Also fix broken Code of Conduct links in issue templates to use
absolute GitHub URLs instead of relative paths that 404.

plugins/python-development/skills/async-python-patterns/SKILL.md

@@ -733,25 +733,3 @@ async def test_with_timeout():
     with pytest.raises(asyncio.TimeoutError):
         await asyncio.wait_for(slow_operation(5), timeout=1.0)
 ```
-
-## Resources
-
-- **Python asyncio documentation**: https://docs.python.org/3/library/asyncio.html
-- **aiohttp**: Async HTTP client/server
-- **FastAPI**: Modern async web framework
-- **asyncpg**: Async PostgreSQL driver
-- **motor**: Async MongoDB driver
-
-## Best Practices Summary
-
-1. **Use asyncio.run()** for entry point (Python 3.7+)
-2. **Always await coroutines** to execute them
-3. **Limit concurrency with semaphores** - unbounded `gather()` can exhaust resources
-4. **Implement proper error handling** with try/except
-5. **Use timeouts** to prevent hanging operations
-6. **Pool connections** for better performance
-7. **Never block the event loop** - use `asyncio.to_thread()` for sync code
-8. **Use semaphores** for rate limiting external API calls
-9. **Handle task cancellation** properly - always re-raise `CancelledError`
-10. **Test async code** with pytest-asyncio
-11. **Stay consistent** - fully sync or fully async, avoid mixing