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/admin/settings.ts

@@ -15,6 +15,7 @@ export const GET: APIRoute = async () => {
     openrouter_key_masked: orMask, openrouter_key_set: !!s.openrouter_key_enc,
     picdrop_host: s.picdrop_host, picdrop_protocol: s.picdrop_protocol, picdrop_port: s.picdrop_port,
     picdrop_user: s.picdrop_user, picdrop_base_path: s.picdrop_base_path,
+    picdrop_default_gallery: s.picdrop_default_gallery,
     picdrop_password_set: !!s.picdrop_password_enc,
     default_dpi: s.default_dpi, default_crop_mode: s.default_crop_mode, concurrency: s.concurrency,
     cricut_sheet_cm: s.cricut_sheet_cm, monthly_budget: s.monthly_budget, n8n_webhook_url: s.n8n_webhook_url,
@@ -29,7 +30,7 @@ export const PATCH: APIRoute = async ({ request }) => {
   if (b.openrouter_key) set('openrouter_key_enc', encrypt(String(b.openrouter_key)));
   if (b.picdrop_password) set('picdrop_password_enc', encrypt(String(b.picdrop_password)));
   for (const col of ['picdrop_host', 'picdrop_protocol', 'picdrop_port', 'picdrop_user', 'picdrop_base_path',
-    'default_dpi', 'default_crop_mode', 'concurrency', 'cricut_sheet_cm', 'monthly_budget', 'n8n_webhook_url']) {
+    'picdrop_default_gallery', 'default_dpi', 'default_crop_mode', 'concurrency', 'cricut_sheet_cm', 'monthly_budget', 'n8n_webhook_url']) {
     if (col in b) set(col, b[col] === '' ? null : b[col]);
   }
   if (!sets.length) return json({ ok: true });