F413 production and verification contract

Producer
- compiler/ContinuationLowering.cpp
- LoopMemoryPhiByteLaneCertificate::isConditional
- loopMemoryPhiByteLaneInitialization
- loopMemoryPhiByteLaneRecord
- bounded-conditional-loop-memoryphi-byte-lane-induction
- symcc-loop-memoryphi-byte-lane-induction-v3

Consumer and runtime
- util/live_continuation.py
- LiveContinuationExecutor._loop_memoryphi_byte_lane_initialization
- exact base/conditional/strided capability closure
- five-block CFG, scalar PHI edge-copy, and block-dominance replay
- integer comparison scalar provenance, widths/ranges, predicate, polarity, and arm identity
- nested header/latch MemoryPhi transcript
- complete versus recurrence-reachable writer aliases
- guarded unique byte owner and load-lane Cartesian product
- bound capacity and whole-domain no-wrap proof
- path-local byte-init authority

Production fixtures and checker
- test/live_conditional_loop_memoryphi_byte_lane_induction.ll
- util/check_live_continuation_lowering.py
- benchmark/generate_conditional_loop_memoryphi_byte_lane_fixture.py

Independent semantics and mechanism cost
- benchmark/check_conditional_loop_memoryphi_byte_lane_oracles.py
- benchmark/benchmark_conditional_loop_memoryphi_byte_lane.py
- test/test_conditional_loop_memoryphi_byte_lane_induction.py

Documentation and diagram
- docs/codex/research-progress/Conditional_Loop_MemoryPhi_Guard_Carry_F413_2026-08-16.md
- docs/codex/diagrams/conditional-loop-memoryphi-guard-carry-f413.svg
- docs/codex/diagrams/conditional-loop-memoryphi-guard-carry-f413.png