feat: Picdrop-style color tags (Rot/Orange/Gruen/Final) in library + in .md metadata; tap-to-open fullscreen for iPhone Save-to-Photos

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XNQ8ghPfzAfsyVYd6HgFb6

src/pages/api/items/index.ts

@@ -19,6 +19,7 @@ export const GET: APIRoute = async ({ url, locals }) => {
   if (!isAdmin && !shared) add('j.created_by = ?', locals.user.uid);
 
   if (q.get('folder')) add('i.folder_id = ?', q.get('folder'));
+  if (q.get('tag')) add('i.color_tag = ?', q.get('tag'));
   if (q.get('delivery')) add('i.delivery_status = ?', q.get('delivery'));
   if (q.get('by')) add('j.created_by = ?', q.get('by'));
   if (q.get('format')) add('i.output_px = ?', q.get('format'));
@@ -28,7 +29,7 @@ export const GET: APIRoute = async ({ url, locals }) => {
   }
 
   const rows = await query(
-    `SELECT i.id, i.filename, i.output_px, i.has_alpha, i.result_path, i.thumb_path, i.folder_id,
+    `SELECT i.id, i.filename, i.output_px, i.has_alpha, i.result_path, i.thumb_path, i.folder_id, i.color_tag,
             i.delivery_status, i.nas_status, i.prompt_used, i.created_at, i.model_used, i.variant_of, j.mode,
             ${(s?.anonymous_generations && !isAdmin) ? 'NULL' : 'u.display_name'} AS by_name,
             j.recipe_snapshot->'tasks' AS tasks