Add OCR debug logging to diagnose receipt extraction quality

Logs per-receipt: OCR text length, first 120 chars of OCR output,
and final parsed vendor/amount/date/product_name.
This will show whether Tesseract is producing usable text.

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

agent_service/agents/expenses_agent.py

@@ -195,6 +195,8 @@ class ExpensesAgent(BaseAgent):
         expense_products = await self._et.get_expense_products()
         default_product_id = expense_products[0]['id'] if expense_products else None
         product_map = {p['id']: p['name'] for p in expense_products}
+        logger.info('expenses_agent: %d receipts received, %d expense products available',
+                    len(receipts), len(expense_products))
 
         # Pass 1: byte-exact dedup
         seen_hashes: set = set()
@@ -208,6 +210,14 @@ class ExpensesAgent(BaseAgent):
                 seen_hashes.add(h)
             unique_receipts.append(r)
 
+        # Log OCR quality for each receipt so we can diagnose extraction failures
+        for r in unique_receipts:
+            raw_text = r.get('text', '') or ''
+            ocr_len = len(raw_text)
+            ocr_preview = raw_text[:120].replace('\n', '↵')
+            logger.info('ocr filename=%r date_hint=%r ocr_len=%d text_preview=%r',
+                        r.get('filename'), r.get('date_from_name'), ocr_len, ocr_preview)
+
         # Parse all receipts concurrently
         parse_tasks = [
             self._parse_receipt_text(
@@ -227,6 +237,9 @@ class ExpensesAgent(BaseAgent):
                 parsed = {'vendor': receipt.get('filename', 'Expense'), 'amount': 0.0,
                           'date': receipt.get('date_from_name') or _date.today().isoformat(),
                           'time': None, 'product_name': ''}
+            logger.info('parsed filename=%r → vendor=%r amount=%s date=%r product=%r',
+                        receipt.get('filename'), parsed.get('vendor'),
+                        parsed.get('amount'), parsed.get('date'), parsed.get('product_name'))
             paired.append((receipt, parsed))
 
         # Pass 2: semantic dedup