fix: support Qt 6.4 DOM parsing in CI

[AhmedAredah]

Summary:

• Keep clang-format advisory without a failed-step annotation.
• Keep CargoNetSim configure/build advisory without failed-step annotations.
• Fix RabbitMQ XML parsing to support Qt 6.4.2, where QDomDocument::setContent() returns bool instead of ParseResult.

Context:

• PR chore: add CI scaffold and CHANGELOG #5 is already merged and its jobs are green, but GitHub still shows red annotations from advisory steps that intentionally exited nonzero.
• CI uses Ubuntu 24.04 apt Qt 6.4.2; local builds may use newer Qt, such as 6.10.1, where setContent() returns QDomDocument::ParseResult.
• This keeps the scaffold non-blocking while making the Actions UI cleaner and removes the source compile error on Qt 6.4.2.

Test plan:

• GitHub Actions run for this PR shows Lint and Build Linux as successful.
• clang-format drift is reported as a warning, not a failed step.
• CargoNetSim builds past SimulationClientBase.cpp on Qt 6.4.2.