[FXC-5449] allow varying refinements on axisymmetric body faces

[alexxu-flex]

Note

Medium Risk
Adds new per-face refinement spacing behavior for AxisymmetricBody and changes nested preprocessing to recurse through dicts as well as lists, affecting meshing JSON generation and unit conversion paths. Risk is moderate due to new validation/translation logic and potential schema/output differences for volume meshing.

Overview
Enables per-face spacing overrides for UniformRefinement on AxisymmetricBody via a new Face reference (AxisymmetricBody.face(i)) and UniformRefinement.face_spacing, with validation to ensure referenced bodies/faces are in-range and part of the refinement.

Updates volume-meshing translation to emit dense faceSpacings arrays for axisymmetric refinements (derived from sparse overrides) while keeping default spacing for unspecified faces, and extends Flow360BaseModel.preprocess recursion to also preprocess nested dict values (not just lists) for unit conversion. Adds comprehensive tests for the new Face type, validation, translation output, unit handling, and JSON round-trips.

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[benflexcompute]

This is too nested and confusing. We need to redesign the interface.

[alexxu-flex]

//User interface
face_spacing={
axisymmetric_body.segments[1] : 0.2*fl.u.cm
}
// Storage side
"face_spacing":{
("entioty_id":"$axisymmetric_body.private_attribute_id", "segment_index": 1) : {"value": 0.2, "units":"cm"}
}

[alexxu-flex]

Then you need a Pydantic model for the "segment" class.

It will be similar relationship between Windtunnel farfield and the windtunnel ghost surfaces.

class Segment(BaseModel):
    type_name:Literal["Segment"]
    entity_id:str
    segment_index: int =pd.Field(min=..., )

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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