feat: custom formats (WxH/stickerN), JPG output option, failed-job status

- format.ts parses free formats from the key: sticker<N> -> N×N cm,
  <W>x<H> -> W×H cm. Fixes 'Unbekanntes Format: sticker5' (the seeded
  'Sticker 5 cm' recipe was unusable) and lets admins define ANY format
  without a migration. Guarded to <=300 cm.
- Output file format PNG/JPG: global default (settings.output_ext) plus
  per-recipe/per-conversion override. JPG only for non-alpha; cutouts
  stay PNG. file.ts sniffs content-type from magic bytes.
- Jobs can now be 'failed' (all items failed) -> red in the queue; add
  finished time to queue list + detail. migration 012.
- Studio: custom-measure input + Dateiformat selector; Admin: global
  Standard-Dateiformat.

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

src/lib/process.ts

@@ -22,6 +22,7 @@ interface RecipeSnapshot {
   prompt_text?: string | null;      // Beschreibung für compose/generate
   delivery?: 'library' | 'picdrop' | 'both';
   picdrop_gallery?: string | null;
+  output_ext?: 'png' | 'jpg' | null;   // Dateiformat-Override; sonst globale Einstellung
 }
 
 /** Welches Modell-ID + Alpha-Fähigkeit? Aus models-Tabelle, sonst Default. */
@@ -130,8 +131,23 @@ export async function processItem(itemId: string): Promise<ProcessResult> {
       hasAlpha = true;
     }
 
+    // Ausgabeformat: Rezept-Override, sonst globale Einstellung. JPG nur ohne Transparenz.
+    const gset = await one<{ output_ext: string | null }>('SELECT output_ext FROM settings WHERE id=1');
+    const wantExt = (r.output_ext || gset?.output_ext || 'png').toLowerCase();
+    let ext = 'png';
+    let contentType = 'image/png';
+    if (wantExt === 'jpg' && !hasAlpha) {
+      outBuf = await sharp(outBuf, { failOn: 'none' })
+        .flatten({ background: '#ffffff' })
+        .withMetadata({ density: dpi })
+        .jpeg({ quality: 92, mozjpeg: true, chromaSubsampling: '4:4:4' })
+        .toBuffer();
+      ext = 'jpg';
+      contentType = 'image/jpeg';
+    }
+
     const key = resultKey(item.id);
-    await putObject(key, outBuf, 'image/png');
+    await putObject(key, outBuf, contentType);
 
     // Vorschaubild (optional, laut Einstellung)
     const cfg = await one<{ make_thumbnails: boolean; keep_sources: boolean; nas_enabled: boolean }>(
@@ -145,7 +161,7 @@ export async function processItem(itemId: string): Promise<ProcessResult> {
       } catch (e) { console.error('[process] Thumbnail fehlgeschlagen', e); }
     }
 
-    const filename = buildResultFilename(item.filename, formatToken(r.output_format), 'png');
+    const filename = buildResultFilename(item.filename, formatToken(r.output_format), ext);
     const outputPx = `${fin.width}x${fin.height}`;
     // Private Aufträge: kein Delivery, kein Backup, kein gespeicherter Prompt.
     const deliveryStatus = (!isPrivate && (r.delivery === 'picdrop' || r.delivery === 'both')) ? 'pending' : 'none';