[rhorvath02]

The old chassis/axle/template hierarchy duplicated assembly choices and mixed calibration, connectors and implementation details. This change migrates the Modelica library to typed VI-derived subsystem contracts, nested owner records and constrained replaceable assemblies, with matching Modelica fixtures.

Includes explicit brake reaction paths and halfshafts, subsystem-owned mounts, wheel compliance, single-axle KnC rigs, package/icon cleanup and diagram routing. Public class paths and record modifiers change. The library migration and its callers stay together because a directory-only split leaves unresolved contracts and class paths.

Scope is the preserved pre-SS release candidate, with a formatting-only MassRecord correction. Python native/FMU tooling, SS/GGV models and SS initialization hooks are excluded. Later GGV-related plant edits are held separately. Existing VehicleFMI and the dynamic steady maneuver remain.

Validation: six standard entry points passed checkModel with balanced equations using OMC 1.27.1/MSL 4.1.0/VI 2.0.2; full-tree Modelica formatting passed. Modelica fixtures accompany the migration; the next PR adds the expanded Python regression harness.

Draft: full simulations and exhaustive OMEdit acceptance have not been rerun for this extracted revision. Existing #30 and #31 need reconciliation with the changed package/record paths; neither is modified by this stack.

Stack (merge bottom-up):

1. [Modelica] Modernize vehicle assemblies and mirrored fixtures #33 — this PR
2. [Tests] Add regression, coverage and diagram checks #34
3. [Release] Wire release gates and document the Modelica migration #35

[rhorvath02]

Superseded by the smaller subsystem stack starting at #37. Full stack index: #54.