fix(evaluator): Honor inc-build flag in warmup prebuilds

[fuyu0425]

Summary

• keep evaluator warmup/eager prebuild enabled for configured benchmarks instead of disabling it when inc_build_enabled=false
• propagate inc_build_enabled through dispatcher warmup, config-mode prebuild, and registration-backed prebuild so disabled configs prebuild clean variants rather than incremental-image work
• add regressions for dispatcher mode, warmup planning, registration serialization, and both prebuild helpers; update the nearest distributed evaluator docs

Testing

• pytest -q tests/test_evaluator_warmup.py tests/test_registry.py tests/test_evaluator_dual_queue.py::TestRunEvaluatorMain::test_dispatcher_mode_keeps_warmup_when_inc_build_disabled tests/test_evaluator_dual_queue.py::TestConfiglessEvaluator::test_enqueue_pre_builds_from_registration_propagates_inc_image_settings tests/test_evaluator_dual_queue.py::TestConfiglessEvaluator::test_enqueue_pre_builds_from_registration_honors_inc_build_disabled tests/test_evaluator_dual_queue.py::TestConfiglessEvaluator::test_enqueue_pre_builds_propagates_inc_image_settings tests/test_evaluator_dual_queue.py::TestConfiglessEvaluator::test_enqueue_pre_builds_honors_inc_build_disabled
• scripts/ci-tests/run-local.sh checks

Notes

• this keeps eager verifier-side cache priming for all benchmarks in the experiment config, but switches that priming from inc-image prep to clean builds when inc_build_enabled is off