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/doctrine/lexer/UPGRADE.md

@@ -0,0 +1,22 @@
+Note about upgrading: Doctrine uses static and runtime mechanisms to raise
+awareness about deprecated code.
+
+- Use of `@deprecated` docblock that is detected by IDEs (like PHPStorm) or
+  Static Analysis tools (like Psalm, phpstan)
+- Use of our low-overhead runtime deprecation API, details:
+  https://github.com/doctrine/deprecations/
+
+# Upgrade to 3.0.0
+
+`Doctrine\Common\Lexer\Token` no longer implements `ArrayAccess`.
+Parameter type declarations have been added to
+`Doctrine\Common\Lexer\AbstractLexer` and `Doctrine\Common\Lexer\Token`.
+You should add both parameter type declarations and return type declarations to
+your lexers, based on the `@return` phpdoc.
+
+# Upgrade to 2.0.0
+
+`AbstractLexer::glimpse()` and `AbstractLexer::peek()` now return
+instances of `Doctrine\Common\Lexer\Token`, which is an array-like class
+Using it as an array is deprecated in favor of using properties of that class.
+Using `count()` on it is deprecated with no replacement.