fix(notion-search): drop unused _flatten_property arg + lock falsy-value behavior

Code review polish:
- Drop the unused `name` parameter from `_flatten_property` (it was
  reserved for future per-property-name special-casing but never used).
- Add a regression test pinning that checkbox=False and number=0 are
  preserved in the enriched output. The existing empty-value filter is
  `if value not in (None, [], "")` which keeps falsy-but-meaningful
  values, but the contract wasn't tested.

22/22 tests pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

custom-skills/31-notion-organizer/code/scripts/test_notion_search.py

@@ -360,6 +360,29 @@ def test_enrich_truncates_long_excerpt():
     _assert(len(enriched[0]["excerpt"]) == 200, "excerpt truncated to 200 chars")
 
 
+def test_enrich_keeps_falsy_but_meaningful_values():
+    """checkbox=False and number=0 are meaningful, not 'empty' — must survive the filter."""
+    from unittest.mock import MagicMock
+    import notion_search
+
+    notion = MagicMock()
+    notion.blocks.children.list.return_value = {"results": []}
+
+    candidate = {
+        "id": "page-a", "url": "https://notion.so/a",
+        "properties": {
+            "Name": {"type": "title", "title": [{"plain_text": "Test"}]},
+            "Active": {"type": "checkbox", "checkbox": False},
+            "Score": {"type": "number", "number": 0},
+        },
+    }
+    enriched = notion_search.enrich_candidates(notion, [candidate])
+    _assert(enriched[0]["properties"].get("Active") is False,
+            "checkbox=False kept (not filtered as 'empty')")
+    _assert(enriched[0]["properties"].get("Score") == 0,
+            "number=0 kept (not filtered as 'empty')")
+
+
 def run_all():
     tests = [
         test_call_claude_dispatches_to_sdk_when_available,
@@ -383,6 +406,7 @@ def run_all():
         test_enrich_extracts_first_paragraph_excerpt,
         test_enrich_falls_back_to_empty_excerpt,
         test_enrich_truncates_long_excerpt,
+        test_enrich_keeps_falsy_but_meaningful_values,
     ]
     for t in tests:
         print(f"\n{t.__name__}")