feat(edint-censo-vehiculos): add Vehicle and Permit candidate models

[albertoabellagarcia]

Summary

Translates the EDINT Vehicle Census/Registry Ontology (v0.1.0) from
https://github.com/EDINT-Ontologia/edint-ontologia-censo-vehiculos — used by
local entities for vehicle tax collection (IVTM in Spain) and mobility
management (parking permits, zone access permits). Closely related to
edint-infraestructura: its Violation.vehicle relationship already
referenced a Vehicle class documented as "referenced but not defined by
the source ontology" — this ontology is that class's real, authoritative
source.

Two entities

• Vehicle: license plate, registered owner, vehicle type, propulsion
  type, environmental badge (Spain's DGT distintivo ambiental).
• Permit: authorised vehicle, authorised street section, permit owner,
  periodicity, status, type, and a date range (activation/beginning/ending).

These are the only two classes in the source ontology with properties of
their own. 6 small controlled vocabularies (2–11 concepts each) are kept as
JSON Schema enums rather than Relationships-to-KOS-URI, since none are
anywhere near the 234-concept scale that made infrastructureType in
edint-infraestructura need the Relationship treatment instead.

The source's Owner class (a union of Person/Organization) is kept as
an opaque Relationship rather than materialized as its own entity — no
generic Person entity is modeled (out of scope, and privacy-sensitive), and
a Relationship value may point at this candidate family's existing
Organization entity when the owner is one.

Two more cross-ontology inconsistencies found, not silently resolved

• Permit.authorisesInSegment points at Vehicle's real, authoritative
  Tramo class in a different, fully external ontology
  (ciudadesabiertas.es) — the same external reference
  edint-infraestructura already superseded internally with its own
  StreetSection entity in its v0.2.1 update. This candidate points at that
  real, current StreetSection entity instead of the stale external
  reference; this vehicle-census ontology just hasn't caught up yet.
• The VehiclePropulsionType SKOS file declares its Diesel concept twice
  (byte-identical, harmless) — flagged for EDINT's awareness, not something
  that needed working around.

Full detail on both, plus why real instance data wasn't usable this time
(the source's real example files are 20–55MB, and the one sampled turned out
to be bare owner-ID stubs keyed by what look like real, partially-visible
Spanish national ID numbers — deliberately not touched), is in
standard-metadata.yaml.

License note

Unlike its siblings (all CC-BY-SA-4.0), this source ontology is CC-BY-4.0 —
same as Smart Data Models' own convention. No license discrepancy to flag
for this one.

Testing

• All schema.json/context.jsonld/example files parse as JSON.
• Both example.json files validate against their own schema.json.
• standard-metadata.yaml parses as YAML.
• Candidates index regenerated.

Note: this branch is based on current master, which does not yet include
the still-open #6 (edint-zona-regulatoria) — no dependency between the two.