chore: remove deprecated flow_boundary and update docs to match new architecture

bindings/python/control_example.ipynb

@@ -25,7 +25,7 @@
    "outputs": [],
    "source": [
     "import entropyk\n",
-    "import numpy as np"
+    "import numpy as np\n"
    ]
   },
   {
@@ -175,11 +175,25 @@
     "except entropyk.SolverError as e:\n",
     "    print(\"Solver error:\", e)\n"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
   }
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "entropyk",
    "language": "python",
    "name": "python3"
   },