Fix incompatible sft pointer types in sf_ntrianglen_init

[cplusv2023]

Problem

sf_ntrianglen_init() expects the shift argument to be float **sft, but several real-valued programs and intermediate functions under user/chenyk still declared and passed it as int **sft.

This caused build failures such as:

error: passing argument 5 of 'sf_ntrianglen_init' from incompatible pointer type
note: expected 'float **' but argument is of type 'int **'

Since GCC 14, incompatible pointer types are treated as errors by default. Although the diagnostic can be downgraded using -Wno-error=incompatible-pointer-types, doing so does not make the code valid: passing int ** where float ** is expected causes the underlying integer data to be accessed as floating-point data, resulting in undefined behavior.

Changes

• Change sft from int ** to float ** throughout the affected real-valued call chains
• Update the corresponding M*.c programs to allocate floating-point shift arrays
• Preserve compatibility with existing integer shift# inputs by reading them into a temporary integer buffer and converting them to float
• Allow floating-point shift# inputs to be read directly
• Keep the complex-valued cntrianglen call chain unchanged

Affected call chains

• sf_ntrianglen_init
• divnn_init
• divnn_sc_init2
• dip3n_init
• odipn_init
• warpscann_init

The primary purpose of this change is to fix the incompatible pointer types in the real-valued non-stationary smoothing implementation.