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/polyfill-php84/Resources/stubs/Pdo/Sqlite.php

@@ -0,0 +1,58 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Pdo;
+
+if (\PHP_VERSION_ID < 80400 && \extension_loaded('pdo_sqlite')) {
+    class Sqlite extends \PDO
+    {
+        public const ATTR_EXTENDED_RESULT_CODES = \PHP_VERSION_ID >= 70400 ? \PDO::SQLITE_ATTR_EXTENDED_RESULT_CODES : 1002;
+        public const ATTR_OPEN_FLAGS = \PHP_VERSION_ID >= 70300 ? \PDO::SQLITE_ATTR_OPEN_FLAGS : 1000;
+        public const ATTR_READONLY_STATEMENT = \PHP_VERSION_ID >= 70400 ? \PDO::SQLITE_ATTR_READONLY_STATEMENT : 1001;
+        public const DETERMINISTIC = \PDO::SQLITE_DETERMINISTIC;
+        public const OPEN_READONLY = \PHP_VERSION_ID >= 70300 ? \PDO::SQLITE_OPEN_READONLY : 1;
+        public const OPEN_READWRITE = \PHP_VERSION_ID >= 70300 ? \PDO::SQLITE_OPEN_READWRITE : 2;
+        public const OPEN_CREATE = \PHP_VERSION_ID >= 70300 ? \PDO::SQLITE_OPEN_CREATE : 4;
+
+        public function __construct(string $dsn, ?string $username = null, ?string $password = null, ?array $options = null)
+        {
+            parent::__construct($dsn, $username, $password, $options);
+
+            if ('sqlite' !== $driver = $this->getAttribute(\PDO::ATTR_DRIVER_NAME)) {
+                throw new \PDOException(\sprintf('Pdo\Sqlite::__construct() cannot be used for connecting to the "%s" driver', $driver));
+            }
+        }
+
+        public static function connect(string $dsn, ?string $username = null, ?string $password = null, ?array $options = null): self
+        {
+            try {
+                return new self($dsn, $username, $password, $options);
+            } catch (\PDOException $e) {
+                throw preg_match('/^Pdo\\\\Sqlite::__construct\(\) cannot be used for connecting to the "([a-z]+)" driver/', $e->getMessage(), $matches) ? new \PDOException(\sprintf('Pdo\Sqlite::connect() cannot be used for connecting to the "%s" driver', $matches[1])) : $e;
+            }
+        }
+
+        public function createAggregate(string $name, callable $step, callable $finalize, int $numArgs = -1): bool
+        {
+            return $this->sqliteCreateAggregate($name, $step, $finalize, $numArgs);
+        }
+
+        public function createCollation(string $name, callable $callback): bool
+        {
+            return $this->sqliteCreateCollation($name, $callback);
+        }
+
+        public function createFunction(string $function_name, callable $callback, int $num_args = -1, int $flags = 0): bool
+        {
+            return $this->sqliteCreateFunction($function_name, $callback, $num_args, $flags);
+        }
+    }
+}