Reorganize: Move all skills to skills/ folder

- Created skills/ directory
- Moved 272 skills to skills/ subfolder
- Kept agents/ at root level
- Kept installation scripts and docs at root level

Repository structure:
- skills/           - All 272 skills from skills.sh
- agents/           - Agent definitions
- *.sh, *.ps1       - Installation scripts
- README.md, etc.   - Documentation

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

commands/write-plan.md

@@ -1,6 +0,0 @@
----
-description: Create detailed implementation plan with bite-sized tasks
-disable-model-invocation: true
----
-
-Invoke the superpowers:writing-plans skill and follow it exactly as presented to you