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/nikic/php-parser/lib/PhpParser/Token.php

@@ -0,0 +1,18 @@
+<?php declare(strict_types=1);
+
+namespace PhpParser;
+
+/**
+ * A PHP token. On PHP 8.0 this extends from PhpToken.
+ */
+class Token extends Internal\TokenPolyfill {
+    /** Get (exclusive) zero-based end position of the token. */
+    public function getEndPos(): int {
+        return $this->pos + \strlen($this->text);
+    }
+
+    /** Get 1-based end line number of the token. */
+    public function getEndLine(): int {
+        return $this->line + \substr_count($this->text, "\n");
+    }
+}