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/twig/string-extra/composer.json

@@ -0,0 +1,32 @@
+{
+    "name": "twig/string-extra",
+    "type": "library",
+    "description": "A Twig extension for Symfony String",
+    "keywords": ["twig", "html", "string", "unicode"],
+    "homepage": "https://twig.symfony.com",
+    "license": "MIT",
+    "minimum-stability": "dev",
+    "authors": [
+        {
+            "name": "Fabien Potencier",
+            "email": "fabien@symfony.com",
+            "homepage": "http://fabien.potencier.org",
+            "role": "Lead Developer"
+        }
+    ],
+    "require": {
+        "php": ">=8.1.0",
+        "symfony/string": "^5.4|^6.4|^7.0|^8.0",
+        "symfony/translation-contracts": "^1.1|^2|^3",
+        "twig/twig": "^3.13|^4.0"
+    },
+    "require-dev": {
+        "symfony/phpunit-bridge": "^6.4|^7.0"
+    },
+    "autoload": {
+        "psr-4" : { "Twig\\Extra\\String\\" : "" },
+        "exclude-from-classmap": [
+            "/Tests/"
+        ]
+    }
+}