Summary

• replace read_wfc_lcao with an explicit two-value init_wfc syntax: init_wfc file txt and init_wfc file binary
• keep the existing init_wfc method field internally while storing the normalized file format separately, so existing PW, LCAO, TDDFT, LR, and EXX flow checks remain stable
• retain the legacy one-value init_wfc file input for backward compatibility (LCAO defaults to text, PW defaults to binary) while canonicalizing INPUT.info to the explicit two-value form
• read the native out_wfc_lcao 2 layout for Gamma-only and multi-k calculations, including type conversion and file/index/dimension validation
• generate binary fixtures at test runtime with the existing writer and cover double, float, complex, skipped bands, mismatched formats, truncated input, and existing text input

Input behavior

• LCAO accepts init_wfc file txt and init_wfc file binary.
• PW accepts init_wfc file binary and rejects init_wfc file txt because no PW text reader exists.
• The selected format is used directly, with no automatic detection or fallback.
• User documentation and CLI help show only the explicit two-value file syntax.

Binary compatibility

The reader intentionally follows the existing native int/double writer protocol. It does not add magic/version fields or cross-ABI, cross-endian compatibility, and it does not read files accumulated with out_app_flag.

Verification

• cmake --build build -j2 (full serial build passed)
• OMP_NUM_THREADS=1 ctest --test-dir /tmp/abacus_wfc_binary_mpi_mpicxx --output-on-failure -R '^(MODULE_IO_read_item_serial|MODULE_IO_write_wfc_nao|MODULE_IO_write_wfc_nao_para|MODULE_IO_read_wfc_nao_test|MODULE_IO_read_wfc_nao_test_parallel)$' (5/5 passed, including 2-rank MPI outside the restricted sandbox)
• OMP_NUM_THREADS=1 two-stage end-to-end runs passed for text Gamma, binary Gamma, and binary 8-k-point LCAO wavefunctions; source/readback energies differed by at most 5.5e-13 eV
• legacy one-value LCAO input read the text file successfully and wrote init_wfc file txt to INPUT.info
• OMP_NUM_THREADS=1 ./build/abacus_basic_omp --check-input: PW file binary passed; PW file txt failed with the expected unsupported-format error
• ./build/abacus_basic_omp -h init_wfc: only the explicit file txt and file binary forms are documented
• ./build/abacus_basic_omp -h read_wfc_lcao: returned Unknown parameter
• regenerated docs/parameters.yaml and docs/advanced/input_files/input-main.md; a fresh YAML generation matched byte-for-byte
• git diff --check
• python3 tools/03_code_analysis/agent_governance_check.py --staged (no findings)

#6206