Use checkout Alembic root in release integration

src/govoplan_core/db/migrations.py

@@ -191,7 +191,20 @@ def registered_module_migration_plan(
 
 
 def _repo_root() -> Path:
-    return Path(__file__).resolve().parents[3]
+    packaged_root = Path(__file__).resolve().parents[3]
+    configured = os.environ.get("GOVOPLAN_CORE_SOURCE_ROOT")
+    candidates = [
+        Path(configured).expanduser() if configured else None,
+        Path.cwd(),
+        packaged_root,
+    ]
+    for candidate in candidates:
+        if candidate is None:
+            continue
+        resolved = candidate.resolve()
+        if (resolved / "alembic.ini").exists() and (resolved / "alembic").is_dir():
+            return resolved
+    return packaged_root
 
 
 def alembic_config(