- Set correct source hash for fetchFromGitLab (was placeholder)
- Add qtdeclarative to build inputs for Qt6::QmlPrivate target
- Patch CMakeLists.txt to find_package(Qt6 QmlPrivate) before QCoro6,
working around QCoro not importing its own transitive dependency
Verified: boxy, zix790prors, and nix-book all build successfully.