Merge DFOModule consensus behavior and update peer announcement transport to DFODecision

[Copilot]

Description

If full description and testing details are included on a parent issue, please link to that here.

Otherwise, please include a summary of the change and which issue is fixed (if any).
Include relevant motivation and context, including a target environment and dunedaq version if known.
Also list any dependencies that are required for this change.
This PR merges standalone and consensus behavior into DFOModule, with consensus controlled by DFOConf::consensus_enabled.
It also incorporates follow-up review feedback by:

• updating DFOCore comments to reflect the single-module architecture, and
• replacing consensus peer announcements from TriggerDecisionToken-based signaling to DFODecision-based signaling.

DFOModule now handles peer announcement send/receive through DFODecision channels, and unit tests were updated accordingly to inject synthetic peer announcements via DFODecision.

Please also include instructions for how a reviewer can test your changes.

1. Configure with a DFOModule where DFOConf.consensus_enabled=true and DFODecision input/output connections are present.
2. Start the module and verify partition formation/peer registration still occurs.
3. Run updated unit tests for DFOModule consensus scenarios in a full DUNE-DAQ build environment.

Type of change

• Documentation (non-breaking change that adds or improves the documentation)
• New feature or enhancement (non-breaking change which adds functionality)
• Optimization (non-breaking change that improves code/performance)
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (whatever its nature)

Testing checklist

• Unit tests pass (e.g. dbt-build --unittest)
• Minimal system quicktest passes (pytest -s minimal_system_quick_test.py)
• Full set of integration tests pass (dunedaq_integtest_bundle.sh)
• Python tests pass if applicable (e.g. python -m pytest)
• Pre-commit hooks run successfully if applicable (e.g. pre-commit run --all-files)

Comments here on the testing

In this sandbox, full package build/test is environment-limited:

• cmake -S . -B ... fails because daq-cmake is not installed.
• ctest reports no discovered tests in the local sandbox context.

Further checks

• Code is commented where needed, particularly in hard-to-understand areas
• Code style is correct (dbt-build --lint, and/or see https://dune-daq-sw.readthedocs.io/en/latest/packages/styleguide/)
• If applicable, new tests have been added or an issue has been opened to tackle that in the future.
  (Indicate issue here: # (issue))

[eflumerf]

@copilot The new module should only inherit from DAQModule. Common DFO code can be moved to library functions in either src or plugins/detail

[Copilot]

@copilot The new module should only inherit from DAQModule. Common DFO code can be moved to library functions in either src or plugins/detail

Done in commit b280c75. DFOConsensusModule now inherits DAQModule directly, with no dependency on DFOModule. All common DFO processing logic (TRB management, slot selection, dispatching, token handling, busy notification, opmon counters) has been extracted into src/dfmodules/DFOCore.hpp/.cpp and added to the library. Both DFOModule and DFOConsensusModule use DFOCore via unique_ptr composition.

[eflumerf]

@copilot Add unit tests for DFOCore

[eflumerf]

@copilot Fix comments in DFOCore since there is only one DFOModule now. Replace announcement using token with announcement using DFODecision

[Copilot]

@copilot Fix comments in DFOCore since there is only one DFOModule now. Replace announcement using token with announcement using DFODecision

Implemented in 6f1aeb6. I updated DFOCore comments to refer to the single DFOModule implementation and switched peer announcements from TriggerDecisionToken to DFODecision (send + receive paths, plus updated unit-test injection paths). No UI changes in this PR, so no screenshot applies.