Fix: Address E2E bugs from real-world MCP testing

Fixes three critical bugs discovered during live testing with Claude:

Bug #1: Same building detection always returned 0
- Root cause: deal.get('address') returned empty string
- Fix: Construct address from streetNameHeb + houseNum fields
- Added test: test_same_building_detection_with_api_fields

Bug #2: Property type filter too strict
- Root cause: Exact match failed for variants like 'דירת גג'
- Fix: Use flexible substring matching with normalization

Bug #3: Deal deduplication used non-existent field
- Root cause: Deduplication key referenced deal.get('address')
- Fix: Removed non-existent field from deduplication key

Also added _calculate_distance() helper for future radius filtering.

Test results: 26/28 passing (2 pre-existing failures unrelated)
References: .cursor/plans/MCP-E2E-TEST-SUMMARY.md

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

tests/test_govmap_client.py

@@ -525,3 +525,22 @@ class TestMarketAnalysisFunctions:
         assert stats["count"] == 3
         assert stats["price_stats"]["mean"] > 0
         assert stats["area_stats"]["mean"] == pytest.approx(80.0)
+
+    def test_same_building_detection_with_api_fields(self):
+        """Test same building detection with actual API field structure."""
+        client = GovmapClient()
+
+        # Test that _is_same_building works with addresses constructed from API fields
+        search_address = "חנקין 62"
+
+        # Deal from same building (should match)
+        deal_address_same = "חנקין 62"
+        assert client._is_same_building(search_address, deal_address_same) is True
+
+        # Deal from different building on same street (should not match)
+        deal_address_different = "חנקין 50"
+        assert client._is_same_building(search_address, deal_address_different) is False
+
+        # Deal from different street (should not match)
+        deal_address_other_street = "בילינסון 6"
+        assert client._is_same_building(search_address, deal_address_other_street) is False