Extract owner-typed corridor records and the typed footprint relation graph

[pinin4fjords]

Parent: #1745

Predecessor: #1747 and its stacked draft PR.

Prototype evidence: draft PR #1743 and checkpoint 3f11f175, especially corridor_cohort_integration.py types near CorridorScalarRequest, CorridorScalarGrant, _FootprintTerm, _FootprintOrder, _FootprintContact, and build_corridor_footprint_witnesses.

Retrieving the prototype: git fetch origin refs/pull/1743/head:pr-1743-checkpoint, then read files with git show 3f11f1758f16341ace6b1409eff53a36a36ec715:<path>. Never check that branch out into your worktree.

The four witness tests to re-establish live in the checkpoint's tests/test_corridor_cohorts.py, not its integration module: test_footprint_witnesses_publish_typed_scalar_ownership_deterministically (line 1430), test_semantic_ledger_claims_store_no_observed_geometry (1729), test_opposite_running_peer_is_not_a_fixed_equality (1994), test_coordinate_proximity_without_a_shared_network_is_not_a_fixed_equality (2024). Re-establish them in tests/test_corridor_cohort_integration.py, since #1747 keeps tests/test_corridor_cohorts.py free of integration imports.

Outcome

Define coordinate-free owner identities and extract the typed footprint/relation graph (witnesses, orders, contacts), without closing components (that is #1749) and without changing production route geometry.

Estimate: 4-6 focused hours, hard maximum one working day. Use a fresh worktree based on the predecessor PR.

Starting reproduction

python -c "from nf_metro.layout.routing.corridor_cohort_integration import build_corridor_footprint_witnesses"  # ModuleNotFoundError

Scope

• Add owner-typed scalar request/grant records with deterministic identity and ordering: CorridorScalarVariable, CorridorScalarRequest, CorridorScalarGrant, CorridorFootprintWitness, _FootprintTerm, _FootprintOrder, _FootprintContact, build_corridor_footprint_witnesses, and the coordinate-free portions of _bind_ledger.
• Port the coordinate-free container types every later child depends on and which no other child names: CorridorCohortLedger, CorridorCohortTarget, CorridorCohortAllocation, CorridorCohortComponentPlan, CorridorCohortLanding, CorridorCohortSegmentKey, and the RoutePlan.corridor_cohort_ledger field. Port their coordinate-free fields only; do not port finalized_owned_segments.
• Extract typed carrier, adjacent lead, landing, connector, endpoint frame, network, direction, region, and per-segment owner witnesses from one route-plan snapshot.
• Represent explicit legal contact and ordered-footprint evidence as a typed relation graph. Do not lower it into solver constraints, and do not compute components over it; Close corridor components over typed footprint relations #1749 owns closure and Complete the member footprint lowering and patch publication slice #1750 owns lowering.
• Prefer one new focused module plus route_reservations.py (whose checkpoint additions claim_is_destination_boundary_carrier, _plan_owned_clearances, canvas_content_band, and _simultaneous_stack_width are reusable starting points); tests live in tests/test_corridor_cohort_integration.py.

Reuse guidance

Reuse the coordinate-free identity, endpoint-rank, exact connector provenance, and direction-qualified owner tests. Do not port the checkpoint's 316-line _member_footprint_model intact: extract the witness/relation-production pieces this issue needs and leave lowering to #1750. Do not port finalized_owned_segments or any proximity-based ownership. Two names used in earlier drafts of this programme, _landing_domains and the landing-obstacle| alias prefix, exist neither on main nor at 3f11f175; ignore them and do not go looking for them.

Non-goals

• No component closure (that is Close corridor components over typed footprint relations #1749).
• No solver invocation or route mutation.
• No convergence request producer.
• No APERTURE mapping.

Code expected to become obsolete

None. This issue deletes no production code.

Acceptance

• Identity collision, serialization/equality, and reversed-input tests pass.
• Proper crossings, endpoint touches, exact continuation contacts, and unrelated same-target/network routes classify deterministically.
• A missing or ambiguous claimed target fails closed.
• Direction and terminal identity are required for legal continuation; same line text or coordinate proximity is insufficient.
• Opposite-running witnesses remain distinct; no relation record gives opposite-running peers equality or rigid bundling.
• Input permutations yield identical witness and relation identities and ordering.
• Ambiguous ownership, duplicate variables, or incomplete witnesses fail closed.

Verification

pytest -q -n 0 tests/test_corridor_cohort_integration.py
ruff check src/nf_metro/layout/routing/corridor_cohort_integration.py src/nf_metro/layout/route_reservations.py src/nf_metro/layout/route_plan.py tests/test_corridor_cohort_integration.py
ruff format --check src/nf_metro/layout/routing/corridor_cohort_integration.py src/nf_metro/layout/route_reservations.py src/nf_metro/layout/route_plan.py tests/test_corridor_cohort_integration.py
mypy

Run the module whole; a -k filter that matches nothing exits 5, which reads like success.

CI and render expectations

This issue must not change a single rendered SVG. Open the PR as a draft based on the predecessor's branch and never merge it to main alone. Mark work-in-progress commits [skip ci]; push the final commit without a skip marker so CI runs, and confirm the render diff reports zero changed renders.

#1653 guardrail and stop condition

This issue describes semantic evidence only. If extraction needs to choose a lane, move a point, inspect a fixture ID, or infer ownership by distance, stop and revise the identity model before continuing.