[Scheduler] Unify per-iteration request intake into ingest_requests()

[hnyls2002]

Collapse the recv + dispatch pair duplicated across all 11 scheduler event loops into a single Scheduler.ingest_requests(), so per-iteration input handling has one home.

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CI States

Latest PR Test (Base): ❌ Run #34182069082
Latest PR Test (Extra): 🚫 Run #34182068913
Latest PR Test (AMD ROCm 7.2): 🚫 Run #34182069104

[hnyls2002]

/tag-and-rerun-ci

[hnyls2002]

/rerun-test test_pp_cp_rank_offsets.py test_mm_shm_error_consensus.py test_batch_result_processor_mamba_boundary.py test_scheduler_stage_metrics.py test/registered/scheduler/test_scheduler_control.py test/registered/pp/test_pp_single_node.py test/registered/disaggregation/test_disaggregation_basic.py
(2 tries)

[github-actions]

Results for /rerun-test test_batch_result_processor_mamba_boundary.py test_mm_shm_error_consensus.py test_pp_cp_rank_offsets.py test_scheduler_timeouts.py test_scheduler_chunked_req_gate.py test_scheduler_decision_batch_params.py test_scheduler_stage_metrics.py test/registered/scheduler/test_scheduler_control.py test/registered/pp/test_pp_single_node.py test/registered/disaggregation/test_disaggregation_basic.py:

🚀 ubuntu-latest (7 tests): ❌ View workflow run

cd test/ && python3 registered/unit/managers/test_batch_result_processor_mamba_boundary.py
cd test/ && python3 registered/unit/managers/test_mm_shm_error_consensus.py
cd test/ && python3 registered/unit/managers/test_pp_cp_rank_offsets.py
cd test/ && python3 registered/unit/managers/test_scheduler_timeouts.py
cd test/ && python3 registered/unit/managers/test_scheduler_chunked_req_gate.py
cd test/ && python3 registered/unit/managers/test_scheduler_decision_batch_params.py
cd test/ && python3 registered/unit/observability/test_scheduler_stage_metrics.py

🚀 1-gpu-5090 (1 test): ✅ View workflow run

cd test/ && python3 registered/scheduler/test_scheduler_control.py

🚀 4-gpu-h100 (1 test): ✅ View workflow run

cd test/ && python3 registered/pp/test_pp_single_node.py

🚀 2-gpu-h100 (1 test): ✅ View workflow run

cd test/ && python3 registered/disaggregation/test_disaggregation_basic.py

[github-actions]

Results for /rerun-test test_pp_cp_rank_offsets.py test_mm_shm_error_consensus.py test_batch_result_processor_mamba_boundary.py test_scheduler_stage_metrics.py test/registered/scheduler/test_scheduler_control.py test/registered/pp/test_pp_single_node.py test/registered/disaggregation/test_disaggregation_basic.py:

🚀 ubuntu-latest (4 tests): ✅ View workflow run

cd test/ && python3 registered/unit/managers/test_pp_cp_rank_offsets.py
cd test/ && python3 registered/unit/managers/test_mm_shm_error_consensus.py
cd test/ && python3 registered/unit/managers/test_batch_result_processor_mamba_boundary.py
cd test/ && python3 registered/unit/observability/test_scheduler_stage_metrics.py

🚀 1-gpu-5090 (1 test): ✅ View workflow run

cd test/ && python3 registered/scheduler/test_scheduler_control.py

🚀 4-gpu-h100 (1 test): ✅ View workflow run

cd test/ && python3 registered/pp/test_pp_single_node.py

🚀 2-gpu-h100 (1 test): ✅ View workflow run

cd test/ && python3 registered/disaggregation/test_disaggregation_basic.py