feat(ocr): show translated progress messages during OCR processing

Backend sends progress codes (PREPARING, LOADING, ANALYZING,
CREATING_BLOCKS:N, DONE:N, ERROR) via OcrJob.progressMessage.
Frontend translates them via Paraglide (de/en/es) and displays
below the spinner.

- V27 migration: adds progress_message column to ocr_jobs
- OcrAsyncRunner updates progress at each phase
- Poll interval reduced to 2s for snappier updates

Refs #226

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/main/java/org/raddatz/familienarchiv/model/OcrJob.java

@@ -47,6 +47,9 @@ public class OcrJob {
     @Builder.Default
     private int skippedCount = 0;
 
+    @Column(name = "progress_message")
+    private String progressMessage;
+
     @Column(name = "created_by")
     private UUID createdBy;
 

backend/src/main/java/org/raddatz/familienarchiv/service/OcrAsyncRunner.java

@@ -37,7 +37,7 @@ public class OcrAsyncRunner {
         if (job == null) return;
 
         job.setStatus(OcrJobStatus.RUNNING);
-        ocrJobRepository.save(job);
+        updateProgress(job, "PREPARING");
 
         OcrJobDocument jobDoc = ocrJobDocumentRepository.findByJobIdAndDocumentId(jobId, documentId)
                 .orElse(null);
@@ -49,9 +49,19 @@ public class OcrAsyncRunner {
         Document doc = documentService.getDocumentById(documentId);
 
         try {
-            processDocument(documentId, doc, userId);
+            updateProgress(job, "LOADING");
+            clearExistingBlocks(documentId);
+            String pdfUrl = fileService.generatePresignedUrl(doc.getFilePath());
+
+            updateProgress(job, "ANALYZING");
+            List<OcrBlockResult> blocks = ocrClient.extractBlocks(pdfUrl, doc.getScriptType());
+
+            updateProgress(job, "CREATING_BLOCKS:" + blocks.size());
+            createTranscriptionBlocks(documentId, blocks, userId, doc.getFileHash());
+
             job.setStatus(OcrJobStatus.DONE);
             job.setProcessedDocuments(1);
+            updateProgress(job, "DONE:" + blocks.size());
             if (jobDoc != null) {
                 jobDoc.setStatus(OcrDocumentStatus.DONE);
                 ocrJobDocumentRepository.save(jobDoc);
@@ -60,13 +70,17 @@ public class OcrAsyncRunner {
             log.error("OCR processing failed for document {}", documentId, e);
             job.setStatus(OcrJobStatus.FAILED);
             job.setErrorCount(1);
+            updateProgress(job, "ERROR");
             if (jobDoc != null) {
                 jobDoc.setStatus(OcrDocumentStatus.FAILED);
                 jobDoc.setErrorMessage(e.getMessage());
                 ocrJobDocumentRepository.save(jobDoc);
             }
         }
+    }
 
+    private void updateProgress(OcrJob job, String message) {
+        job.setProgressMessage(message);
         ocrJobRepository.save(job);
     }
 

backend/src/main/resources/db/migration/V27__add_progress_message_to_ocr_jobs.sql

@@ -0,0 +1 @@
+ALTER TABLE ocr_jobs ADD COLUMN progress_message TEXT;