DNG/RAW photo support for gallery upload

- Server: accept .dng in OCR endpoint (PIL opens as TIFF)
- Server: bump OCR size limit to 20MB (DNG files can be large)
- Client: gallery upload tries server OCR first (with 6s timeout),
  then falls back to client-side Tesseract.js — matches 📸 capture flow
- DNG photos now work with 'Pick from Gallery'

static/index.html

@@ -2638,7 +2638,28 @@
         if (ocrEl) ocrEl.textContent = '⏳ Running OCR...';
 
         try {
-          const ocrData = await ocrImageClient(file);
+          // Try server OCR first (handles more formats like DNG/RAW)
+          let ocrData = null;
+          try {
+            const controller = new AbortController();
+            const t = setTimeout(() => controller.abort(), 6000);
+            const fd = new FormData();
+            fd.append('file', file, file.name || 'sticker.jpg');
+            const res = await fetch('/api/ocr', {
+              method: 'POST', body: fd, signal: controller.signal,
+              headers: AppState.authToken
+                ? { 'Authorization': 'Bearer ' + AppState.authToken } : {},
+            });
+            clearTimeout(t);
+            if (res.ok) {
+              ocrData = await res.json();
+            }
+          } catch (_) { /* server OCR failed, fall through to client */ }
+
+          if (!ocrData || !ocrData.machine_id) {
+            // Fall back to client-side Tesseract.js
+            ocrData = await ocrImageClient(file);
+          }
           if (ocrData && ocrData.machine_id) {
             document.getElementById('scanMachineId').value = ocrData.machine_id;
             if (ocrEl) ocrEl.innerHTML = `✅ Machine ID: <strong>${esc(ocrData.machine_id)}</strong>` +