🔥 Add initial database migrations, seeders, and factories

🎨 Refactor `Lecturer` model to include new fields and factory usage
🔧 Update `DatabaseSeeder` to handle default seeds
🛠️ Enhance `einundzwanzig` database configuration for SQLite compatibility

database/migrations/2026_05_02_155303_create_lecturers_table.php

@@ -0,0 +1,29 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('lecturers', function (Blueprint $table) {
+            $table->id();
+            $table->string('name');
+            $table->string('slug')->nullable()->index();
+            $table->text('bio')->nullable();
+            $table->string('npub', 63)->nullable()->index();
+            $table->string('pubkey', 64)->nullable()->index();
+            $table->string('website')->nullable();
+            $table->boolean('active')->default(true);
+            $table->unsignedBigInteger('created_by')->nullable();
+            $table->timestamps();
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('lecturers');
+    }
+};