Fix module_hs sparse output controls

[goodchong]

Summary

• stabilize module_hs sparse CSR threshold counting and r(R) header generation
• wire out_mat_t/dh/ds/r precision options into sparse writers while preserving legacy defaults
• add regression coverage for dH/dS sparse CSR, SOC directions, r(R) finalization, and single-R precision

Tests

• git diff --check
• g++ -std=c++17 -Isource -c source/source_io/module_hs/rr_sparse_writer.cpp -o /tmp/rr_sparse_writer.o
• g++ -std=c++17 -Isource -c source/source_io/module_hs/single_R_io.cpp -o /tmp/single_R_io.o

Full CMake targets were not run because this checkout has no existing build directory.