Fix: Enable substring matching for OCR, InvoiceNumber, Bankgiro, Plusgiro

Previously substring matching was only enabled for date fields, causing
OCR values embedded in longer tokens like "Fakturanummer: 2465027205"
to not be matched.

Changes:
- Extended Strategy 4 (substring match) to numeric fields
- Updated _find_substring_matches to support OCR, InvoiceNumber, Bankgiro, Plusgiro

This should significantly improve match rates for these fields.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/matcher/field_matcher.py

@@ -106,8 +106,9 @@ class FieldMatcher:
                 fuzzy_matches = self._find_fuzzy_matches(page_tokens, value, field_name)
                 matches.extend(fuzzy_matches)
 
-            # Strategy 4: Substring match (for dates embedded in longer text)
+            # Strategy 4: Substring match (for values embedded in longer text)
-            if field_name in ('InvoiceDate', 'InvoiceDueDate'):
+            # e.g., "Fakturanummer: 2465027205" should match OCR value "2465027205"
+            if field_name in ('InvoiceDate', 'InvoiceDueDate', 'InvoiceNumber', 'OCR', 'Bankgiro', 'Plusgiro'):
                 substring_matches = self._find_substring_matches(page_tokens, value, field_name)
                 matches.extend(substring_matches)
 
@@ -240,16 +241,19 @@ class FieldMatcher:
         """
         Find value as a substring within longer tokens.
 
-        Handles cases like 'Fakturadatum: 2026-01-09' where the date
+        Handles cases like:
-        is embedded in a longer text string.
+        - 'Fakturadatum: 2026-01-09' where the date is embedded
+        - 'Fakturanummer: 2465027205' where OCR/invoice number is embedded
+        - 'OCR: 1234567890' where reference number is embedded
 
-        Uses lower score (0.75) than exact match to prefer exact matches.
+        Uses lower score (0.75-0.85) than exact match to prefer exact matches.
-        Only matches if the value appears as a distinct segment (not part of a number).
+        Only matches if the value appears as a distinct segment (not part of a larger number).
         """
         matches = []
 
-        # Only use for date fields - other fields risk false positives
+        # Supported fields for substring matching
-        if field_name not in ('InvoiceDate', 'InvoiceDueDate'):
+        supported_fields = ('InvoiceDate', 'InvoiceDueDate', 'InvoiceNumber', 'OCR', 'Bankgiro', 'Plusgiro')
+        if field_name not in supported_fields:
             return matches
 
         for token in tokens: