fix(demo): remove unpinned coordinode override from Colab install block

Previous fix installed coordinode from the git pin inside IN_COLAB, but
the unconditional subprocess.run at the end of the cell still installed
bare "coordinode" from PyPI — pip treated this as an upgrade and
overrode the pinned version with whatever PyPI resolved to.

Align 00/01/02 with 03's pattern: single _coordinode_spec variable that
evaluates to the git-pin URL when IN_COLAB else bare "coordinode" for
local dev.

Author: polaz

demo/notebooks/00_seed_data.ipynb

@@ -105,28 +105,20 @@
     "        check=True,\n",
     "        timeout=600,\n",
     "    )\n",
-    "    # SDK (gRPC client helpers used by LocalClient wrapper) must come from the same pin.\n",
-    "    subprocess.run(\n",
-    "        [\n",
-    "            sys.executable,\n",
-    "            \"-m\",\n",
-    "            \"pip\",\n",
-    "            \"install\",\n",
-    "            \"-q\",\n",
-    "            \"git+https://github.com/structured-world/coordinode-python.git@c2ce32064dd7f6495f0998049c0cc2f6f7a5767d#subdirectory=coordinode\",\n",
-    "        ],\n",
-    "        check=True,\n",
-    "        timeout=300,\n",
-    "    )\n",
     "\n",
+    "_coordinode_spec = (\n",
+    "    \"git+https://github.com/structured-world/coordinode-python.git@c2ce32064dd7f6495f0998049c0cc2f6f7a5767d#subdirectory=coordinode\"\n",
+    "    if IN_COLAB\n",
+    "    else \"coordinode\"\n",
+    ")\n",
     "subprocess.run(\n",
     "    [\n",
     "        sys.executable,\n",
     "        \"-m\",\n",
     "        \"pip\",\n",
     "        \"install\",\n",
     "        \"-q\",\n",
-    "        \"coordinode\",\n",
+    "        _coordinode_spec,\n",
     "        \"nest_asyncio\",\n",
     "    ],\n",
     "    check=True,\n",

demo/notebooks/01_llama_index_property_graph.ipynb

@@ -93,32 +93,24 @@
     "        check=True,\n",
     "        timeout=600,\n",
     "    )\n",
-    "    # SDK (gRPC client helpers used by LocalClient wrapper) must come from the same pin.\n",
-    "    subprocess.run(\n",
-    "        [\n",
-    "            sys.executable,\n",
-    "            \"-m\",\n",
-    "            \"pip\",\n",
-    "            \"install\",\n",
-    "            \"-q\",\n",
-    "            \"git+https://github.com/structured-world/coordinode-python.git@c2ce32064dd7f6495f0998049c0cc2f6f7a5767d#subdirectory=coordinode\",\n",
-    "        ],\n",
-    "        check=True,\n",
-    "        timeout=300,\n",
-    "    )\n",
     "\n",
     "# coordinode-embedded is pinned to a specific git commit because it requires a Rust\n",
     "# build (maturin/pyo3) and the embedded engine must match the Python SDK version.\n",
     "# The remaining packages (coordinode, llama-index, etc.) are installed without pins:\n",
     "# they are pure Python, release frequently, and pip resolves a compatible version.\n",
+    "_coordinode_spec = (\n",
+    "    \"git+https://github.com/structured-world/coordinode-python.git@c2ce32064dd7f6495f0998049c0cc2f6f7a5767d#subdirectory=coordinode\"\n",
+    "    if IN_COLAB\n",
+    "    else \"coordinode\"\n",
+    ")\n",
     "subprocess.run(\n",
     "    [\n",
     "        sys.executable,\n",
     "        \"-m\",\n",
     "        \"pip\",\n",
     "        \"install\",\n",
     "        \"-q\",\n",
-    "        \"coordinode\",\n",
+    "        _coordinode_spec,\n",
     "        \"llama-index-graph-stores-coordinode\",\n",
     "        \"llama-index-core\",\n",
     "        \"nest_asyncio\",\n",

demo/notebooks/02_langchain_graph_chain.ipynb

@@ -90,19 +90,6 @@
     "        check=True,\n",
     "        timeout=600,\n",
     "    )\n",
-    "    # SDK (gRPC client helpers used by LocalClient wrapper) must come from the same pin.\n",
-    "    subprocess.run(\n",
-    "        [\n",
-    "            sys.executable,\n",
-    "            \"-m\",\n",
-    "            \"pip\",\n",
-    "            \"install\",\n",
-    "            \"-q\",\n",
-    "            \"git+https://github.com/structured-world/coordinode-python.git@c2ce32064dd7f6495f0998049c0cc2f6f7a5767d#subdirectory=coordinode\",\n",
-    "        ],\n",
-    "        check=True,\n",
-    "        timeout=300,\n",
-    "    )\n",
     "\n",
     "# coordinode-embedded and langchain-coordinode are pinned to a specific git commit:\n",
     "# - coordinode-embedded requires a Rust build (maturin/pyo3); the embedded engine\n",
@@ -111,14 +98,19 @@
     "#   is available; this parameter is not yet released to PyPI.\n",
     "# The remaining packages (coordinode, LangChain, etc.) are installed without pins:\n",
     "# they are pure Python, release frequently, and pip resolves a compatible version.\n",
+    "_coordinode_spec = (\n",
+    "    \"git+https://github.com/structured-world/coordinode-python.git@c2ce32064dd7f6495f0998049c0cc2f6f7a5767d#subdirectory=coordinode\"\n",
+    "    if IN_COLAB\n",
+    "    else \"coordinode\"\n",
+    ")\n",
     "subprocess.run(\n",
     "    [\n",
     "        sys.executable,\n",
     "        \"-m\",\n",
     "        \"pip\",\n",
     "        \"install\",\n",
     "        \"-q\",\n",
-    "        \"coordinode\",\n",
+    "        _coordinode_spec,\n",
     "        \"langchain\",\n",
     "        \"git+https://github.com/structured-world/coordinode-python.git@c2ce32064dd7f6495f0998049c0cc2f6f7a5767d#subdirectory=langchain-coordinode\",\n",
     "        \"langchain-community\",\n",