fix: create project-thumbnails bucket in instrumentation.ts (#118)

The thumbnail upload (uploadProjectThumbnail) writes to a
'project-thumbnails' storage bucket, but instrumentation.ts only
bootstrapped the 'avatars' bucket.  This caused:

  Upload failed: Bucket not found

Add the missing bucket creation with matching constraints (public,
10 MB limit, image/png only).  Also refactor the bucket-exists check
to use a Set so it scales cleanly as more buckets are added.

Co-authored-by: Anton Pascal <anton-pascal@users.noreply.github.com>

apps/editor/instrumentation.ts

@@ -10,9 +10,9 @@ export async function register() {
     const supabase = createClient(url, key)
 
     const { data: buckets } = await supabase.storage.listBuckets()
-    const exists = buckets?.some((b) => b.name === 'avatars')
+    const bucketNames = new Set(buckets?.map((b) => b.name))
 
-    if (!exists) {
+    if (!bucketNames.has('avatars')) {
       await supabase.storage.createBucket('avatars', {
         public: true,
         fileSizeLimit: 5 * 1024 * 1024, // 5MB
@@ -20,5 +20,14 @@ export async function register() {
       })
       console.log('Created "avatars" storage bucket')
     }
+
+    if (!bucketNames.has('project-thumbnails')) {
+      await supabase.storage.createBucket('project-thumbnails', {
+        public: true,
+        fileSizeLimit: 10 * 1024 * 1024, // 10MB (matches uploadProjectThumbnail validation)
+        allowedMimeTypes: ['image/png'],
+      })
+      console.log('Created "project-thumbnails" storage bucket')
+    }
   }
 }