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/Policies/ProjectFilePolicy.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace App\Policies;
+
+use App\Models\Project;
+use App\Models\ProjectFile;
+use App\Models\User;
+
+class ProjectFilePolicy
+{
+    /**
+     * Guards against IDOR: a file only downloads through the project it actually belongs to.
+     */
+    public function download(User $user, ProjectFile $file, Project $project): bool
+    {
+        return $user->role === 'admin' && $file->revision->project_id === $project->id;
+    }
+}