Add PermissionCheck dataclass with parent/child fields, refs #2528

Instead of logging permission checks as dicts with a 'resource' key,
use a typed dataclass with separate parent and child fields.

Changes:
- Created PermissionCheck dataclass in app.py
- Updated permission check logging to use dataclass
- Updated PermissionsDebugView to use dataclass attributes
- Updated PermissionCheckView to check parent/child instead of resource
- Updated permissions_debug.html template to display parent/child
- Updated test expectations to use dataclass attributes

This provides better type safety and cleaner separation between
parent and child resource identifiers.

tests/test_permissions.py

@@ -1259,9 +1259,10 @@ async def test_actor_restrictions(
             "response_status": response.status_code,
             "checks": [
                 {
-                    "action": check["action"],
-                    "resource": check["resource"],
-                    "result": check["result"],
+                    "action": check.action,
+                    "parent": check.parent,
+                    "child": check.child,
+                    "result": check.result,
                 }
                 for check in perms_ds._permission_checks
             ],