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>

skills/plugins/claude-hud/tests/fixtures/expected/render-basic.txt

@@ -0,0 +1,5 @@
+[Opus] █████░░░░░ 45%
+my-project
+◐ Edit: .../authentication.ts | ✓ Read ×1
+✓ explore [haiku]: Finding auth code (<1s)
+▸ Add tests (1/2)