[Bug] set_range_style overwrites formulas with values

[getmateri]

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Affected packages and versions

0.15.5-insiders.20260214-994a4f5

Reproduction link

Reproduce by:

1. Call set_range_data to create a range of formulas
2. Call set_range_style to add formating to this same range
3. Observe formulas become replaced with computed values

Expected behavior

Calling set_range_style on a range of formula cells should only change formatting and preserve formulas.

set_range_style is not style-isolated; it goes through the same internal handler as data writes, and that handler applies style by calling setValue(...) on the range.

Actual behavior

Calling set_range_style on a range of formula sets all cells as values.

System information

No response