migrate template: Add function to read the project type

Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

Author: llucax

.github/cookiecutter-migrate.template.py

@@ -21,6 +21,7 @@
 """  # noqa: E501
 
 import hashlib
+import json
 import os
 import subprocess
 import tempfile
@@ -36,6 +37,28 @@ def main() -> None:
     print("=" * 72)
 
 
+def read_project_type() -> str | None:
+    """Read the cookiecutter project type from the replay file."""
+    replay_path = Path(".cookiecutter-replay.json")
+    if not replay_path.exists():
+        return None
+
+    try:
+        data = json.loads(replay_path.read_text(encoding="utf-8"))
+    except (json.JSONDecodeError, OSError):
+        return None
+
+    cookiecutter_data = data.get("cookiecutter")
+    if not isinstance(cookiecutter_data, dict):
+        return None
+
+    project_type = cookiecutter_data.get("type")
+    if not isinstance(project_type, str):
+        return None
+
+    return project_type
+
+
 def apply_patch(patch_content: str) -> None:
     """Apply a patch using the patch utility."""
     subprocess.run(["patch", "-p1"], input=patch_content.encode(), check=True)