Add debug build support in CI

[vkraleti]

Extend the GitHub workflows to build debug variants in CI. These builds are produced
with DEBUG_BUILD=1 and are intended for long‑running stability testing, providing
additional logging and diagnostics to help analyze system behavior and failures.

[lumag]

As we discussed several times, " long‑running stability testing" is not supposed to be executed on the debug builds. Those builds enable several features which significantly change runtime behaviour.

[ndechesne]

As we discussed several times, " long‑running stability testing" is not supposed to be executed on the debug builds. Those builds enable several features which significantly change runtime behaviour.

this was discussed more. we agreed to enable these builds to have them available when we need to debug a specific issue. when our perf/stability (or any dev team) finds an issue with a build, they will want to flash the 'debug' build to see if they can get additional information.

[ricardosalveti]

This will add several new build runs, should we wait for the split between nightly / weekly? It is not clear to me how often these builds will be required.

[lumag]

As we discussed several times, " long‑running stability testing" is not supposed to be executed on the debug builds. Those builds enable several features which significantly change runtime behaviour.

this was discussed more. we agreed to enable these builds to have them available when we need to debug a specific issue. when our perf/stability (or any dev team) finds an issue with a build, they will want to flash the 'debug' build to see if they can get additional information.

It's fine. However I still see the "long-running stability testing" as the main reason for this change. The commit message should reflect the fact that these builds are to be used only for debugging the issue and only in case the main image can't help.