fix(gallery): fill tall portrait cards to full block width with object-cover crop

- ArtworkCard: add w-full to nova-card-media, use absolute inset-0 on img so
  object-cover fills the max-height capped box instead of collapsing the width
- MasonryGallery.css: add width:100% to media container, position img
  absolutely so top/bottom is cropped rather than leaving dark gaps
- Add React MasonryGallery + ArtworkCard components and entry point
- Add recommendation system: UserRecoProfile model/DTO/migration,
  SuggestedCreatorsController, SuggestedTagsController, Recommendation
  services, config/recommendations.php
- SimilarArtworksController, DiscoverController, HomepageService updates
- Update routes (api + web) and discover/for-you views
- Refresh favicon assets, update vite.config.js

tests/Feature/Recommendations/UserPreferenceBuilderTest.php

@@ -0,0 +1,81 @@
+<?php
+
+declare(strict_types=1);
+
+use App\DTOs\UserRecoProfileDTO;
+use App\Models\Artwork;
+use App\Models\User;
+use App\Models\UserRecoProfile;
+use App\Services\Recommendation\UserPreferenceBuilder;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\DB;
+
+uses(RefreshDatabase::class);
+
+// ─────────────────────────────────────────────────────────────────────────────
+// UserRecoProfileDTO
+// ─────────────────────────────────────────────────────────────────────────────
+
+it('DTO serialises and round-trips correctly', function () {
+    $dto = new UserRecoProfileDTO(
+        topTagSlugs:      ['space', 'nature'],
+        topCategorySlugs: ['wallpapers'],
+        strongCreatorIds: [1, 2, 3],
+        tagWeights:       ['space' => 0.6, 'nature' => 0.4],
+        categoryWeights:  ['wallpapers' => 1.0],
+    );
+
+    $arr = $dto->toArray();
+    $restored = UserRecoProfileDTO::fromArray($arr);
+
+    expect($restored->topTagSlugs)->toBe(['space', 'nature'])
+        ->and($restored->topCategorySlugs)->toBe(['wallpapers'])
+        ->and($restored->strongCreatorIds)->toBe([1, 2, 3])
+        ->and($restored->tagWeight('space'))->toBe(0.6)
+        ->and($restored->followsCreator(2))->toBeTrue()
+        ->and($restored->followsCreator(99))->toBeFalse();
+});
+
+it('DTO hasSignals returns false for empty profile', function () {
+    $empty = new UserRecoProfileDTO();
+    expect($empty->hasSignals())->toBeFalse();
+});
+
+it('DTO hasSignals returns true when tags are present', function () {
+    $dto = new UserRecoProfileDTO(topTagSlugs: ['space']);
+    expect($dto->hasSignals())->toBeTrue();
+});
+
+// ─────────────────────────────────────────────────────────────────────────────
+// UserPreferenceBuilder
+// ─────────────────────────────────────────────────────────────────────────────
+
+it('UserPreferenceBuilder returns empty DTO for user with no activity', function () {
+    $user    = User::factory()->create();
+    $builder = app(UserPreferenceBuilder::class);
+
+    $dto = $builder->build($user);
+
+    expect($dto)->toBeInstanceOf(UserRecoProfileDTO::class)
+        ->and($dto->topTagSlugs)->toBe([])
+        ->and($dto->strongCreatorIds)->toBe([]);
+});
+
+it('UserPreferenceBuilder persists profile row on first build', function () {
+    $user    = User::factory()->create();
+    $builder = app(UserPreferenceBuilder::class);
+
+    $builder->buildFresh($user);
+
+    expect(UserRecoProfile::find($user->id))->not->toBeNull();
+});
+
+it('UserPreferenceBuilder produces stable output on repeated calls', function () {
+    $user    = User::factory()->create();
+    $builder = app(UserPreferenceBuilder::class);
+
+    $first  = $builder->buildFresh($user)->toArray();
+    $second = $builder->buildFresh($user)->toArray();
+
+    expect($first)->toBe($second);
+});