feat: add auto-generated CI documentation pre-commit hook (#2890)

# What does this PR do?
Our CI is entirely undocumented, this commit adds a README.md file with
a table of the current CI and what is does

---------

Signed-off-by: Nathan Weinberg <nweinber@redhat.com>

scripts/gen-ci-docs.py

@@ -0,0 +1,77 @@
+#!/usr/bin/env python
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+from pathlib import Path
+
+import yaml
+
+REPO_ROOT = Path(__file__).parent.parent
+
+
+def parse_workflow_file(file_path):
+    """Parse a workflow YAML file and extract name and run-name."""
+    try:
+        with open(file_path, encoding="utf-8") as f:
+            content = yaml.safe_load(f)
+
+        name = content["name"]
+        run_name = content["run-name"]
+
+        return name, run_name
+    except Exception as e:
+        raise Exception(f"Error parsing {file_path}") from e
+
+
+def generate_ci_docs():
+    """Generate the CI documentation README.md file."""
+
+    # Define paths
+    workflows_dir = REPO_ROOT / ".github/workflows"
+    readme_path = workflows_dir / "README.md"
+
+    # Header section to preserve
+    header = """# Llama Stack CI
+
+Llama Stack uses GitHub Actions for Continous Integration (CI). Below is a table detailing what CI the project includes and the purpose.
+
+| Name | File | Purpose |
+| ---- | ---- | ------- |
+"""
+
+    # Get all .yml files in workflows directory
+    yml_files = []
+    for file_path in workflows_dir.glob("*.yml"):
+        yml_files.append(file_path)
+
+    # Sort files alphabetically for consistent output
+    yml_files.sort(key=lambda x: x.name)
+
+    # Generate table rows
+    table_rows = []
+    for file_path in yml_files:
+        name, run_name = parse_workflow_file(file_path)
+        filename = file_path.name
+
+        # Create markdown link in the format [filename.yml](filename.yml)
+        file_link = f"[{filename}]({filename})"
+
+        # Create table row
+        row = f"| {name} | {file_link} | {run_name} |"
+        table_rows.append(row)
+
+    # Combine header and table rows
+    content = header + "\n".join(table_rows) + "\n"
+
+    # Write to README.md
+    with open(readme_path, "w", encoding="utf-8") as f:
+        f.write(content)
+
+    print(f"Generated {readme_path} with {len(table_rows)} workflow entries")
+
+
+if __name__ == "__main__":
+    generate_ci_docs()