feat: all AI formats printable, crop-vs-border rule, mobile layout, Passbilder rename

Print now offers every format the AI pipeline knows (9x13 to 60x90, DIN A6-A2,
squares, poster/frame sizes to 70x100, and the screen ratios as physical sizes).
When a picture does not match the target ratio the user picks per image between
cropping to fill and keeping the whole picture on a border colour - never a
stretch. The module is called Passbilder now; /druck redirects.

Fixes two real defects: sharp runs extend after resize, so padded cells came out
oversized (a 35x45 mm cell became 35x171 mm with a border), and the grid packer
rotated a single portrait photo just because more would fit sideways.

Mobile: cards become rows, touch targets ~40px, crop editor as a bottom sheet.
Verified at 390/820/1440px - all three produce the same PDF.

src/pages/api/print/single.ts

@@ -31,7 +31,10 @@ export const POST: APIRoute = async ({ request, locals }) => {
     const dpi = Math.min(1200, Math.max(72, Number(body?.dpi) || 300));
     const ext: 'jpg' | 'png' = body?.ext === 'png' ? 'png' : 'jpg';
     const buf = await loadSource(src, locals.user as any);
-    const out = await renderCell(buf, crop, size.w, size.h, dpi, { ext, bleedMm: Number(body?.bleedMm) || 0 });
+    const fit = body?.fit === 'contain' ? 'contain' : 'cover';
+    const background = /^#[0-9a-f]{6}$/i.test(String(body?.bg || '')) ? String(body.bg) : '#ffffff';
+    const out = await renderCell(buf, crop, size.w, size.h, dpi,
+      { ext, bleedMm: Number(body?.bleedMm) || 0, fit, background });
 
     // Hinweis, falls die Quelle für echte 300 dpi zu klein ist.
     const cropW = (crop?.w ?? 1) * out.srcPx[0];