Fix: Multitouch compilation errors (InputDevice) and trigger full ARM build matrix

[matt2005]

Summary:
This PR merges the latest changes from develop into main to resolve the GitHub Actions build failures on main (run 19346066133) caused by:

1. Invalid call to parent_.setAttribute(Qt::WA_AcceptTouchEvents, true) — parent is a QObject (QApplication::instance()), not a QWidget.
2. Use of unsupported enum value ACTION_CANCEL — not defined in PointerAction.proto; replaced with ACTION_UP semantics for cancel.

Changes:

• Updated src/autoapp/Projection/InputDevice.cpp:
  • Removed setAttribute() call on QObject parent.
  • Mapped TouchCancel to ACTION_UP and cleared touch state safely.

Context:
The failing build on main (commit 2cc4c31) blocked packaging for all architectures. A successful build on develop (run 19346834208) validated the fix for amd64 (bookworm & trixie). Opening this PR will run the full matrix (including arm64/armhf) via the PR workflow to confirm cross-arch stability before merging.

Testing Performed:

• GitHub Actions (develop branch): amd64 builds passed, test and packaging steps succeeded.
• No behavioural regression expected: multitouch event handling falls back gracefully; cancel events treated as full release.

Risk & Mitigation:

• Low risk: isolated to InputDevice.cpp multitouch init and cancel handling.
• If any ARM-specific issues arise, they will be visible in this PR's CI run.

Follow-Up (if needed):

• Add a small markdown doc summarising multitouch protocol mapping.
• Hardware validation on Raspberry Pi 7" touch panel.

Checklist:

• Builds on develop (amd64) succeed.
• Fixes compile errors (QObject::setAttribute & ACTION_CANCEL).
• ARM builds green in PR CI.
• Merge with "Squash and Merge" per repository guidelines.

Please review and approve once matrix is green.