6.99.15: Enable packaging for pxf-fdw7 (#10)

* ci: create pxf-fdw7 deb package

- enable package workflow for version 7
- uncomment deb-packages-pxf7 matrix entry in Release CI

* build(deb): remove dh-python dependency

No Python code is being packaged;
dh-python helpers are not invoked

* ci(package): improve observability for skipped packaging jobs

- Add `[SKIPPED]` prefix to the job name when `skip_package` is true
- Generate a Markdown report in `$GITHUB_STEP_SUMMARY` to provide clear context in the Actions UI
- Emit a `::notice` workflow annotation to highlight skipped matrix configurations

* ci(package): bump tests/install/deb v44 to v45

Update actions/download-artifact v4 to v8 - Node 24 support

* ci(build): move 24.04 prod build from nightly to PR only

There's no point in repeating the nightly build on not changed prod image

* fix(ci): use nightly matrix only on schedule trigger, skip package job on schedule

Invert build matrix condition: schedule -> nightly, everything else -> PR/release.
Add if: github.event_name != 'schedule' to package job so nightly runs only test

Task: CI-6141