Add HL3D branding, Etsy Live/Draft paging and Projects lifecycle

Replace the old touchmark/PNG identity with the supplied lockup and
monogram, segmented role-aware navigation, Live/Draft listing filters
with generation-based cache invalidation, and admin Projects covering
immutable file revisions, listing live pointers, and exact-decimal
filament/packaging/shipping costing. Additive schema only; no Etsy
publication. Isolated clone tests: 301 tests, 1162 assertions.

app/Models/ProjectListingLink.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace App\Models;
+
+use Database\Factories\ProjectListingLinkFactory;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class ProjectListingLink extends Model
+{
+    /** @use HasFactory<ProjectListingLinkFactory> */
+    use HasFactory;
+
+    public const ALL_VARIATIONS = 'all';
+
+    protected $fillable = [
+        'project_id', 'shop_id', 'listing_id', 'variation_key', 'title_snapshot',
+        'state_snapshot', 'remote_updated_at', 'synced_at', 'live_release_id',
+        'lock_version', 'created_by', 'detached_at',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'remote_updated_at' => 'datetime',
+            'synced_at' => 'datetime',
+            'detached_at' => 'datetime',
+        ];
+    }
+
+    public function project(): BelongsTo
+    {
+        return $this->belongsTo(Project::class);
+    }
+
+    public function liveRelease(): BelongsTo
+    {
+        return $this->belongsTo(ProjectRelease::class, 'live_release_id');
+    }
+
+    public function creator(): BelongsTo
+    {
+        return $this->belongsTo(User::class, 'created_by');
+    }
+
+    public function isDetached(): bool
+    {
+        return $this->detached_at !== null;
+    }
+}