chore(docs): consolidate docs to docs/ directory, clean root

- Move CHANGELOG.md, CONTRIBUTING.md, SECURITY.md to docs/
- Move SCOOP.engineer-friendly.tool.md and Win11_tools.engineer-friendly.tool.md to docs/
- Rename docs/Security.md -> docs/Security-Inventory.md (was P/Invoke inventory;
  avoids conflict with incoming SECURITY.md security policy)
- Delete current-ids.txt (generated tweak ID list; already in .gitignore)
- Update README.md CONTRIBUTING link to docs/CONTRIBUTING.md
- Root now contains only README.md plus required config/tooling files

Author: aeger

Readme.md

@@ -339,7 +339,7 @@ new TweakDef
 }
 ```
 
-See [CONTRIBUTING.md](CONTRIBUTING.md) for the full guide.
+See [CONTRIBUTING.md](docs/CONTRIBUTING.md) for the full guide.
 
 ## Building the Installer