test(fit): add score_time clock integration test

[clanghans]

What

Adds a feature integration test (FIT) for the score_time clock library.
score_time is already pinned in known_good.json (and the generated
bazel_common/score_modules_target_sw.MODULE.bazel), but so far it had no
integration test coverage. This adds one following the existing FIT pattern
(C++ scenario binary + pytest driver).

Scope

Three C++ scenarios exercise the public Clock<Tag> API and self-validate,
throwing (process exit 101) on failure:

• time.system_clock_now — SystemClock::Now() tracks the host system clock
  within a generous tolerance (catches an epoch-zero stub / unlinked backend).
• time.steady_clock_now — two SteadyClock::Now() readings are monotonic.
• time.high_res_steady_clock_now — HighResSteadyClock::Now() is non-zero and
  monotonic.

Each scenario emits its reading as a structured JSON log line. The pytest FIT
case (tests/time/test_clock_now.py) drives each scenario and asserts the exit
code plus the emitted reading. score_time is C++ only, so the tests are
parametrized with version=["cpp"].

Deferred (not in this PR): VehicleTime (requires explicit Init()), and the
time_daemon / time_slave / ts_client processes (better suited to ITF/QEMU tests).

Files

• feature_integration_tests/test_scenarios/cpp/src/scenarios/time/ — new scenarios + group mod.cpp
• feature_integration_tests/test_scenarios/cpp/src/internals/time/clock_log.h — small JSON log helper
• feature_integration_tests/test_scenarios/cpp/src/scenarios/mod.cpp — register the time group
• feature_integration_tests/test_scenarios/cpp/BUILD — add the three @score_time clock deps
• feature_integration_tests/test_cases/tests/time/test_clock_now.py — pytest FIT case

Verification

• bazel build --config=linux-x86_64 //feature_integration_tests/test_scenarios/cpp:cpp_test_scenarios — builds with the score_time deps.
• Ran each scenario binary directly — exit 0 with valid readings.
• bazel test --config=linux-x86_64 //feature_integration_tests/test_cases:fit_cpp — all tests pass (6 new time tests + existing suite).
• Python (ruff) and Starlark (buildifier) format checks pass.

[PiotrKorkus]

good for basic smoke tests

did you consider any feature reqs? could you add the mapping?

I would suggest adding a scenario where we do a couple of ticks in a loop, assert all are not decreasing, then sleep for some known duration and compare again next tick.

[PiotrKorkus]

redundant? should be possible to use FitScenario directly

[clanghans]

Dropped the build_tools override — FitScenario.build_tools already resolves the parametrized version via request.getfixturevalue. ClockScenario is kept as a thin base only to provide test_config, which is abstract on Scenario and not implemented by FitScenario.

[anmittag]

@clanghans any update on your PR, there are some findings....

[clanghans]

Both addressed in 0b66ca82.

Feature req mapping: added @add_test_properties on each test class, mapping to the score_time feature requirements:

• TestSystemClockNow → FR-9 (Absolute Time Base API)
• TestHighResSteadyClockNow → FR-13 (High Precision Clock API)
• TestSteadyClockNow, TestSteadyClockProgression → FR-14 (Monotonic Clock API)

Marked partially_verifies since each test covers one aspect (live reading / monotonicity / progression), not the full requirement.

Loop / sleep / compare scenario: added steady_clock_progression (C++) and TestSteadyClockProgression (Python). The scenario takes N readings (default 5), asserts the sequence is non-decreasing, sleeps a known duration (default 100 ms), takes a final reading, and asserts it does not precede the last. Python additionally checks the post-sleep gap is at least half the sleep duration (jitter tolerance). This covers the TC-FR14-001 "call Now() repeatedly, assert strictly increasing" case.

[clanghans]

@anmittag Updated. The three findings from PiotrKorkus are addressed in 0b66ca82 — dropped the redundant ClockScenario.build_tools override, added feature-requirement mapping (FR-9 / FR-13 / FR-14), and added a steady-clock progression scenario that loops ticks, sleeps, and compares. Clock tests pass locally; the 6 UTF-8 persistency errors in test_combined_requirements.py are pre-existing on main (KVS init failure, unrelated to this PR).