fix(network): TASK_PHASE_ERROR handling, CancelTask notification, yaml phase validation

[mvillmow]

Summary

• GetTaskResult does not handle TASK_PHASE_ERROR #225: GetTaskResult now returns a distinct, descriptive error message when a task ends in TASK_PHASE_ERROR (infrastructure/unexpected error), differentiating it from other non-completed terminal states.
• CancelTask: notify assigned agent on cancellation #224: CancelTask sends a CANCEL_TASK KeystoneMessage to the assigned agent via the (optionally-wired) IMessageRouter after marking a task cancelled, enabling cooperative cancellation. A new setMessageRouter() method exposes this wiring point.
• yaml_parser::parseStatus should validate phase strings against enum #222: yaml_parser::parseStatus now validates the phase string against the known hmas::TaskPhase enum values using the new public isKnownPhaseString() / stringToPhase() utilities in include/network/task_phase_utils.hpp. Unknown phase strings cause parseTaskSpec to return std::nullopt.

Changes

• include/network/task_phase_utils.hpp: Added public phaseToString, stringToPhase, and isKnownPhaseString inline functions (previously only private static methods on HMASCoordinatorServiceImpl).
• include/network/hmas_coordinator_service.hpp: Added optional IMessageRouter* member and setMessageRouter() setter.
• src/network/hmas_coordinator_service.cpp: Implemented setMessageRouter; updated GetTaskResult and CancelTask as described above.
• src/network/yaml_parser.cpp: Added phase validation in parseStatus; catch block broadened to std::exception so the validation error propagates correctly.

Test plan

• Existing test_task_phase_utils.cpp continues to pass (terminal state detection, cleanup, etc.)
• Build with cmake --preset debug && cmake --build --preset debug — no new warnings
• GetTaskResult test: set task to TASK_PHASE_ERROR, call GetTaskResult, verify response contains the infrastructure-error message
• CancelTask test: wire a mock IMessageRouter, cancel a task, verify routeMessage was called with a CANCEL_TASK message addressed to the assigned agent
• yaml_parser test: parse a spec with status.phase: "BOGUS_PHASE" — parseTaskSpec returns std::nullopt; valid phase strings still parse correctly

🤖 Generated with Claude Code

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Security Scan Results

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• ✅ SAST: Completed (check Security tab for details)
• ✅ Dependency Scanning: Completed
• ✅ C++ Static Analysis: Completed
• ✅ Docker Image Scanning: 0 high, 22 medium vulnerabilities (acceptable)

Recommendations

• Review findings in the GitHub Security tab
• Check artifact uploads for detailed reports
• Address critical Docker vulnerabilities immediately

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Workflow: Security Scanning