fix(client,demo): reject bool schema_mode, guard _EMBEDDED_PIP_SPEC reference

- _normalize_schema_mode: explicitly reject bool before int branch —
  True/False would previously be accepted as int 1/0 silently
- notebook 03 connect cell: use globals().get('_EMBEDDED_PIP_SPEC', fallback)
  so the ImportError message is actionable even when the cell runs standalone

Author: polaz

coordinode/coordinode/client.py

@@ -512,6 +512,8 @@ def _normalize_schema_mode(schema_mode: str | int, mode_map: dict[str, int]) ->
         - ``int`` — must be one of the values in *mode_map*; allows round-tripping
           ``LabelInfo.schema_mode`` / ``EdgeTypeInfo.schema_mode`` back into the call.
         """
+        if isinstance(schema_mode, bool):
+            raise ValueError(f"schema_mode must be a str or int, got bool {schema_mode!r}.")
         if isinstance(schema_mode, int):
             # Accept int to allow round-tripping LabelInfo/EdgeTypeInfo.schema_mode.
             valid_ints = set(mode_map.values())

demo/notebooks/03_langgraph_agent.ipynb

@@ -179,9 +179,16 @@
     "    try:\n",
     "        from coordinode_embedded import LocalClient\n",
     "    except ImportError as exc:\n",
+    "        # _EMBEDDED_PIP_SPEC is defined in the install cell; fall back to the\n",
+    "        # pinned spec so this cell remains runnable if executed standalone.\n",
+    "        _pip_spec = globals().get(\n",
+    "            \"_EMBEDDED_PIP_SPEC\",\n",
+    "            \"git+https://github.com/structured-world/coordinode-python.git\"\n",
+    "            \"@8da94d694ecaabee6f8380147d02f08220061bfa#subdirectory=coordinode-embedded\",\n",
+    "        )\n",
     "        raise RuntimeError(\n",
     "            \"coordinode-embedded is not installed. \"\n",
-    "            f\"Run: pip install {_EMBEDDED_PIP_SPEC}\"\n",
+    "            f\"Run: pip install {_pip_spec}\"\n",
     "            \" — or start a CoordiNode server and set COORDINODE_ADDR.\"\n",
     "        ) from exc\n",
     "\n",