CK: Refactor 144 contraction instance files with shared CK_CONTRACTION_INSTANCE macro

[AviralGoelAMD]

Depends on #6324

Summary

Refactor all 144 contraction library instance .cpp files (bilinear + scale, 2D/6D, f32/f64/bf16/cf32/cf64) to use a shared CK_CONTRACTION_INSTANCE macro defined in contraction_instance_common.hpp. Each 58-line file is reduced to 12 lines — zero unique logic, pure parameterization.

Metric	Value
Files changed	145 (144 instances + 1 new shared header)
Insertions	+1,373
Deletions	−7,890
Net lines removed	−6,517

What changed

Before	After
144 instance files, each ~58 lines of identical boilerplate (includes, namespace, type alias, registration function) differing only in 12 template parameters	1 shared macro header + 144 files at ~12 lines each (copyright + include + macro invocation)

Macro parameters (12)

CK_CONTRACTION_INSTANCE(INST_TPL, OP_NAME, CDE_OP, NDIM_VAL, NAME_SUFFIX,
    ADATA, BDATA, ACC, CSHUFFLE, DS_TUPLE, EDATA, COMPUTE)

Parameter	Example	Purpose
INST_TPL	device_contraction_kk_instance	Device template to instantiate
OP_NAME	bilinear	Lowercase, used in ## token pasting for function/type names
CDE_OP	Bilinear	C++ type name (capitalized) for template args
NDIM_VAL	2 or 6	Number of dimensions
NAME_SUFFIX	f32_f32_f32_f32_kknn	Data type + layout suffix
ADATA..COMPUTE	F32, F32, ...	Template type arguments

Readability assessment

A code realist review confirmed this change improves readability: the original 58-line files contained zero unique logic — just mechanical boilerplate wrappers that varied only in 12 template parameters. After the macro, each file's intent is immediately clear from a single macro call, and the 12 parameters serve as a concise specification of what the instance does (data types, layout, operation). Adding a new contraction instance requires writing 1 line instead of copying and modifying 58 lines. The realist also noted that the area has very low activity (1 functional commit in 18 months), so merge conflict risk is negligible.

Cumulative cleanup series stats

PR	Description	Net lines
#6300	Remove 61 dead #if 0 blocks	−2,648
#6302	Remove 41 commented-out dead code blocks	−2,861
#6303	Remove 4 orphaned files	−3,886
#6323	Extract gemm_quant test boilerplate	−693
#6324	Extract contraction example boilerplate	−1,016
This PR	Refactor 144 contraction instance files	−6,517
Total		−17,621