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/league/csv/src/CannotInsertRecord.php

@@ -0,0 +1,64 @@
+<?php
+
+/**
+ * League.Csv (https://csv.thephpleague.com)
+ *
+ * (c) Ignace Nyamagana Butera <nyamsprod@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace League\Csv;
+
+/**
+ * Thrown when a data is not added to the Csv Document.
+ */
+class CannotInsertRecord extends Exception
+{
+    /** The record submitted for insertion. */
+    protected array $record = [];
+    /** Validator which did not validate the data. */
+    protected string $name = '';
+
+    /**
+     * Creates an Exception from a record insertion into a stream.
+     */
+    public static function triggerOnInsertion(array $record): self
+    {
+        $exception = new self('Unable to write record to the CSV document');
+        $exception->record = $record;
+
+        return $exception;
+    }
+
+    /**
+     * Creates an Exception from a Record Validation.
+     */
+    public static function triggerOnValidation(string $name, array $record): self
+    {
+        $exception = new self('Record validation failed');
+        $exception->name = $name;
+        $exception->record = $record;
+
+        return $exception;
+    }
+
+    /**
+     * Returns the validator name.
+     */
+    public function getName(): string
+    {
+        return $this->name;
+    }
+
+    /**
+     * Returns the invalid data submitted.
+     */
+    public function getRecord(): array
+    {
+        return $this->record;
+    }
+}