Switch to Wagtail theme and add comprehensive tutorial notebooks

- Switch Sphinx documentation from groundwork-sphinx-theme to sphinx-wagtail-theme for better code block readability
- Add comprehensive tutorial notebooks for all cluster types:
  * SLURM tutorial with HPC job scheduling examples
  * PBS/Torque tutorial with batch system execution patterns
  * SGE tutorial with Sun Grid Engine distributed computing
  * Kubernetes tutorial with containerized execution
  * SSH tutorial with direct remote server execution
- Add complete API demonstration notebook covering all user-facing functions
- Update Sphinx configuration to include Interactive Notebooks section
- Update cluster support status table to accurately reflect SGE and Kubernetes as "Nearly Ready" instead of "In Progress"
- All notebooks include Google Colab integration with correct master branch links

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: jeremymanning

docs/notebooks/basic_usage.ipynb

@@ -3,17 +3,8 @@
   {
    "cell_type": "markdown",
    "metadata": {},
-   "source": [
-    "# Clustrix Basic Usage Tutorial\n",
-    "\n",
-    "[![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/ContextLab/clustrix/blob/main/docs/notebooks/basic_usage.ipynb)\n",
-    "\n",
-    "This notebook demonstrates the basic usage of Clustrix for distributed computing.\n",
-    "\n",
-    "## Installation\n",
-    "\n",
-    "First, let's install Clustrix:"
-   ]
+   "source": "# Clustrix Basic Usage Tutorial\n\n[![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/ContextLab/clustrix/blob/master/docs/notebooks/basic_usage.ipynb)\n\nThis notebook demonstrates the basic usage of Clustrix for distributed computing.\n\n## Installation\n\nFirst, let's install Clustrix:",
+   "outputs": []
   },
   {
    "cell_type": "code",
@@ -356,4 +347,4 @@
  },
  "nbformat": 4,
  "nbformat_minor": 4
-}
+}