refactor: Cleanup git state - commit all staged changes

Major refactoring cleanup:
- Add new controller architecture (class-controller-*.php)
- Add new settings-v2 UI (views/settings-v2/)
- Add new CSS architecture (agentic-sidebar.css, tokens)
- Add esbuild build pipeline (scripts/build.js, package.json)
- Add composer dependencies (vendor/)
- Add frontend src directory (assets/js/src/index.jsx)
- Add documentation files
- Remove old/obsolete files (class-settings.php, old CSS)

This commits all pending changes from previous refactoring efforts.

vendor/symfony/contracts/Translation/README.md

@@ -0,0 +1,9 @@
+Symfony Translation Contracts
+=============================
+
+A set of abstractions extracted out of the Symfony components.
+
+Can be used to build on semantics that the Symfony components proved useful and
+that already have battle tested implementations.
+
+See https://github.com/symfony/contracts/blob/main/README.md for more information.