v0.4.3

Contact API documentation now distinguishes mechanical and thermal
contact interfaces, eliminating fictitious force_normal /
force_shear advertisements on thermal contacts and adding version
gating for the PFC 9.0-only VertexFacetContact. Rblock contacts
and thermal-specific power methods join their respective interfaces
as first-class entries.

Fixed

• pfc_browse_python_api / pfc_query_python_api no longer falsely
  advertise mechanical force methods on thermal contacts. The five
  *ThermalContact types (BallBallThermalContact,
  BallFacetThermalContact, BallPebbleThermalContact,
  PebblePebbleThermalContact, PebbleFacetThermalContact) are
  now documented through a dedicated ThermalContact interface that
  exposes contact state, geometry, grouping, model/property, and
  orientation methods — without force_normal / force_shear.
  Verified against the live PFC 9 bridge: 0 cross-contamination
  across all 15 contact classes. Closes #10.
• VertexFacetContact is now correctly tagged as PFC 9.0-only via
  per-type availability.versions, so 6.0 / 7.0 queries no longer
  suggest it exists on those versions.

Added

• Mechanical Contact interface now expands to all four rblock
  contact types (BallRBlockContact, PebbleRBlockContact,
  RBlockFacetContact, RBlockRBlockContact) and the 9.0-only
  VertexFacetContact, matching the official PFC class hierarchy.
• Thermal-specific power() / set_power(value) methods are now
  documented for all five thermal contact types, sourced from the
  official PFC 9 Python HTML reference.