F421 source and contract inventory

compiler/ContinuationLowering.cpp
  - symcc-loop-memoryphi-byte-lane-induction-v11
  - bounded-nested-loop-memoryphi-decision-dag-value-summary
  - postorder shared Decision DAG construction and finite specialization

util/live_continuation.py
  - strict actual-IR DAG reconstruction
  - topology, depth, reachability, affine leaf, ABI, path and witness checks

util/check_live_continuation_lowering.py
  - v11 expectation flag and capability closure
  - certificate and actual-lowered-program mutation battery

test/live_nested_loop_memoryphi_decision_dag_value.ll
test/live_nested_loop_memoryphi_decision_dag_value_fallback.ll
test/test_nested_loop_memoryphi_decision_dag_value.py
  - runtime, endian, sharing, mixed-writer, depth and rejection coverage

benchmark/generate_nested_loop_memoryphi_decision_dag_fixture.py
benchmark/check_nested_loop_memoryphi_decision_dag_oracles.py
benchmark/benchmark_nested_loop_memoryphi_decision_dag.py
  - parameterized fixture, independent finite oracle and mechanism benchmark