Fix 8 bugs from second code review

HIGH:
- Fix JS TypeError on empty API response: validate keys/types are arrays
  before using them; add HTTP status check (resp.ok)
- Fix BEGIN IMMEDIATE conflict: set isolation_level=None (autocommit) on
  SQLite connection so explicit transactions work without implicit ones

MEDIUM:
- Fix import_json_file non-atomic: wrap entire operation in BEGIN/COMMIT
  with ROLLBACK on error — no more partial imports
- Fix crash on non-dict batch_data items: skip non-dict elements
- Fix comma-in-key corruption: store keys/types as JSON arrays in hidden
  widgets instead of comma-delimited strings (backward-compat fallback)
- Fix blocking I/O in API routes: change async def to def so FastAPI
  auto-threads the synchronous SQLite calls

LOW:
- Fix missing ?. on app.graph.setDirtyCanvas in refreshDynamicOutputs

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

tests/test_db.py

@@ -272,6 +272,44 @@ class TestImport:
         s1 = db.get_sequence(df_id_2, 1)
         assert s1["prompt"] == "v2"
 
+    def test_import_skips_non_dict_batch_items(self, db, tmp_path):
+        """Non-dict elements in batch_data should be silently skipped, not crash."""
+        pid = db.create_project("p1", "/p1")
+        json_path = tmp_path / "mixed.json"
+        data = {KEY_BATCH_DATA: [
+            {"sequence_number": 1, "prompt": "valid"},
+            "not a dict",
+            42,
+            None,
+            {"sequence_number": 3, "prompt": "also valid"},
+        ]}
+        json_path.write_text(json.dumps(data))
+        df_id = db.import_json_file(pid, json_path)
+
+        seqs = db.list_sequences(df_id)
+        assert seqs == [1, 3]
+
+    def test_import_atomic_on_error(self, db, tmp_path):
+        """If import fails partway, no partial data should be committed."""
+        pid = db.create_project("p1", "/p1")
+        json_path = tmp_path / "batch.json"
+        data = {KEY_BATCH_DATA: [{"sequence_number": 1, "prompt": "hello"}]}
+        json_path.write_text(json.dumps(data))
+        db.import_json_file(pid, json_path)
+
+        # Now try to import with bad data that will cause an error
+        # (overwrite the file with invalid sequence_number that causes int() to fail)
+        bad_data = {KEY_BATCH_DATA: [{"sequence_number": "not_a_number", "prompt": "bad"}]}
+        json_path.write_text(json.dumps(bad_data))
+        with pytest.raises(ValueError):
+            db.import_json_file(pid, json_path)
+
+        # Original data should still be intact (rollback worked)
+        df = db.get_data_file(pid, "batch")
+        assert df is not None
+        s1 = db.get_sequence(df["id"], 1)
+        assert s1["prompt"] == "hello"
+
 
 # ------------------------------------------------------------------
 # Query helpers

tests/test_project_loader.py

@@ -86,6 +86,20 @@ class TestProjectLoaderDynamic:
         assert result[2] == 1.5
         assert len(result) == MAX_DYNAMIC_OUTPUTS
 
+    def test_load_dynamic_with_json_encoded_keys(self):
+        """JSON-encoded output_keys should be parsed correctly."""
+        import json as _json
+        data = {"my,key": "comma_val", "normal": "ok"}
+        node = ProjectLoaderDynamic()
+        keys_json = _json.dumps(["my,key", "normal"])
+        with patch("project_loader._fetch_data", return_value=data):
+            result = node.load_dynamic(
+                "http://localhost:8080", "proj1", "batch_i2v", 1,
+                output_keys=keys_json
+            )
+        assert result[0] == "comma_val"
+        assert result[1] == "ok"
+
     def test_load_dynamic_empty_keys(self):
         node = ProjectLoaderDynamic()
         with patch("project_loader._fetch_data", return_value={"prompt": "hello"}):