feat: model selection+visibility, better filenames, picdrop direct upload + configurable gallery

- studio: quality/model selector (friendly names from active models); library shows model used
- seed 2 models (Schnell/Beste Qualitaet); GET /api/models for studio+library
- filename: YYYY-MM-DD_motif_format.png (was redundant slug, no date)
- picdrop: direct upload to final name (fix .tmp- leftover from failed rename on picdrop); cleanupTmp helper
- configurable default gallery (migration 003, settings + admin field); base_path=SFTP root, gallery=subfolder

src/pages/api/items/index.ts

@@ -24,7 +24,7 @@ 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.folder_id,
-            i.delivery_status, i.created_at, u.display_name AS by_name,
+            i.delivery_status, i.created_at, i.model_used, u.display_name AS by_name,
             j.recipe_snapshot->'tasks' AS tasks
        FROM items i
        JOIN jobs j ON j.id = i.job_id