PR-A0: manual witness API repin (post-#6520 structural termination)

[briansrls]

Summary

PR-A for Wave 1 criterion 1 (general body producer), building on merged anchor #6526 and implementation #6520.

#6520 removed descent fuel (remaining / body_lowering_descent) from body_lowering_fold — termination is now structural via the normalize child-fold. The manual body-lowering witnesses (body_lowering_normalize_add, body_lowering_match, body_lowering_projection_call) still called the pre-#6520 Outcome+remaining signatures and failed to resolve.

This PR re-pins those witnesses to the current API (Optional for unwrap/domain/infix helpers; Outcome without remaining for arrow/match/postfix paths) and updates the match-arm navigation RED control note for structural termination.

Not in scope (later PR-B→E): FLAG E row-fold, resolve param-scaffold dissolution, Stage B/C/D.

Test plan

• claim_batch --entry src/v2/test/claim/manual/body_lowering_normalize_add.dag --function body_lowering_normalize_yields_arrow — PASS
• claim_batch --entry src/v2/test/claim/manual/body_lowering_match.dag --function body_lowering_match_lowers_to_match --function body_lowering_match_unnavigable_arm_refuses --function body_lowering_normalized_module_has_match — PASS
• claim_batch --entry src/v2/test/claim/manual/body_lowering_projection_call.dag --function body_lowering_projection_lowers_to_transform — PASS
• claim_batch --entry src/v2/test/claim/body_lowering_wrapper_retained_test.dag --function body_lowering_wrapper_retained_diagnostics_holds — PASS
• claim_batch --entry src/v2/test/claim/body_lowering_well_formed_wall_test.dag — both fns PASS
• claim_batch --entry src/v2/test/claim/self_host/wave1_gate1_general_body_producer_witness_test.dag --function wave1_gate1_body_producer_modules_import_resolve_holds — PASS (no regression on test(self-host): Wave 1 gate 1 general body producer verification witnesses #6526 anchor)

[gunbai-bot]

Verified the composer-2.5 approval against current HEAD (ff287cdb):

• No stale remaining: or node_subtree_count imports/calls remain in the three witness files (grep clean).
• Call sites match post-body lowering dissolution #6520 signatures: body_lower_unwrap_captured / body_lower_try_infix_transform → Optional; body_lower_wire_match_arm_capture / body_lower_fn_decl_to_arrow → Outcome without fuel args.
• Unnavigable-arm RED control correctly pins ^body_lowering_reason_match_arm_navigation_refused under structural termination.

No fix commit warranted — mechanical alignment only, scope matches PR-A intent.

— sent from silent-lynx-25

[gunbai-bot]

Verified the claude-opus-4-7 approval against HEAD (ff287cdb):

• Each callsite in the three witness files matches the current body_lowering_fold signatures (body_lower_unwrap_captured / _try_infix_transform → Optional; _wire_match_arm_capture / _fn_decl_to_arrow → Outcome without remaining).
• unnavigable_arm_budget_note correctly documents structural termination (no fuel budget) and the RED control still pins ^body_lowering_reason_match_arm_navigation_refused.

No fix commit warranted — tests-only mechanical alignment, already covered by prior verification comment.

— sent from silent-lynx-25