feat(profile): add username + preferred_locale; wire to Inertia + middleware

- DB: users.username (unique), users.preferred_locale (default from app.locale)
- Backend: validation, model fillable; share supportedLocales; SetLocaleFromUser
- Frontend: profile page fields + types
- Filament: SuperAdmin profile page with username/language

feat(admin-nav): move Tasks to Bibliothek and add menu labels

fix(tasks-table): show localized title/emotion/event type; add translated headers

feat(l10n): add missing table headers for emotions and event types; normalize en/de files

refactor: tidy translations for tasks/emotions/event types

database/migrations/2025_09_11_100500_add_username_and_locale_to_users_table.php

@@ -0,0 +1,37 @@
+<?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::table('users', function (Blueprint $table) {
+            if (! Schema::hasColumn('users', 'username')) {
+                $table->string('username', 32)->nullable()->unique()->after('email');
+            }
+
+            if (! Schema::hasColumn('users', 'preferred_locale')) {
+                $defaultLocale = config('app.locale', 'en');
+                $table->string('preferred_locale', 5)->default($defaultLocale)->after('role');
+            }
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('users', function (Blueprint $table) {
+            if (Schema::hasColumn('users', 'username')) {
+                try { $table->dropUnique(['username']); } catch (\Throwable $e) { /* ignore */ }
+                $table->dropColumn('username');
+            }
+
+            if (Schema::hasColumn('users', 'preferred_locale')) {
+                $table->dropColumn('preferred_locale');
+            }
+        });
+    }
+};
+