[Onlyti]

Physical +y rack displacement now reaches L5 hardpoint geometry when steer_input="rack_travel". The default roadwheel path retains its previous steering output contract.

Acceptance and fixed conditions

• Original locked eight-value product-toe table and tolerances unchanged: front +/-2%, rear 1e-6 deg.
• Loaded fixture, hardpoints, contact and load model retained; 1 ms steps, zero rack for the first 0.2 s, deadline 8 s.
• Zero/positive/negative runs advance at identical times. The first common 0.5 s consecutive window requires body speed <=0.001 m/s, angular speed <=0.001 rad/s, every wheel travel rate <=0.001 m/s, toe rate <=0.01 deg/s and vertical load rate <=1 N/s; all monitored channels finite and all loads positive.
• No hardcoded acceptance time, unloaded substitute, fixed wheel position, later favourable-time search or permanent-equilibrium claim.
• T6 checks both rack signs at settlement. T8 independently compares both signs with Ackerman 0/100 byte-for-byte. T9 removes the actual direct-read expression, fails the formal test, then restores and passes (raw logs).

Post-measurement changes

• 4159e41 restores the shared UnitySteering contract; product defaults and frozen fixtures have zero diff from 94113b6.
• 5dca79e introduces a test-only physical RackOutput and compares zero/input at the same time instead of subtracting an earlier control observation.
• 155b727 incorporates the approved first-common-settlement assertions as a separate test commit; locked table, tolerances and product geometry remain unchanged.
• e10bb55 is a document-only currency confirmation (docs/VALIDATION.md). Measurement tree remains c63aa1f.

Local verification

HEAD at measurement: c63aa1f
Confirmation HEAD: e10bb55
Canonical serial validation: 595/595.
Main registration: 587; additions: L5RackTravel.T1T2_DefaultMatchesRoadwheel, L5RackTravel.T3_RackWithoutHardpointThrows, L5RackTravel.T4_RackPlusDynamicThrows, L5RackTravel.T5T6T8_LockedTableAndSameSign, L5RackTravel.T7_BadKeyThrows, L5RackTravel.T8_AckermanDoesNotChangeRackOutput, L5RackTravel.T9_DisableEnvFailsT5ThenRestores, l5_rack_travel; removals: none.
Language counts: {"Python": 45, "C++": 550}.
Baseline 94113b6 vs current: ten serialized file pairs (L1-L5, omitted/explicit roadwheel) byte-identical.
D0FlatContactBaseline and restored targeted C++/Python acceptance pass.
mkdocs strict rc=0. Documentation audit FAIL count matches main after currency fill.

CI measurement

Same-head measurement run 41351185235 (head c63aa1f):

attempt	jobs	fail-0 lines of 595	timing/known_failure exec
1	5/5 success	5	0
2	5/5 success	5	0
3	5/5 success	5	0

Confirmation run 41360044716 (head e10bb55, VALIDATION 1 file):

attempt	jobs	fail-0 lines of 595	timing/known_failure exec
1	5/5 success	5	0

Wheels 41360143451 (head e10bb55): ubuntu-latest, windows-latest, sdist, verify success; publish skipped.
No merge, tag or publication performed.

Documentation impact

Updated hardpoint-kinematics section and CHANGELOG input-contract table; no changes to other levels' rack meaning. Raw evidence: /home/ailab-12/q48b/settlement/ and /home/ailab-12/q48b/followup/.