Calculations of Twist operators

[k-ido]

This pull request introduces comprehensive documentation and code updates to support the calculation and output of Twist operators in the mVMC software. The changes include new sections in both English and Japanese documentation describing the input and output file formats for Twist operators and the associated lattice definitions, as well as updates to the codebase to properly average and output these new quantities.

Code and test updates for Twist operator:

• Added calculators for Twist operator in src/mVMC/calgrn.c and src/mVMC/calgrn_fsz.c.
• Modified the Green function averaging routine in src/mVMC/average.c to include Twist operator results in the averaging process.
• Added workspace and variable initialization for Twist operator calculations.
• Added tests for Twist operator caluculations in test/python/data/Twist_SSH_cmp and test/python/data/Twist_SSH_fsz.

Documentation updates for Twist operators:

• Added detailed explanations and examples for specifying Twist operators in the input file twist.def, including parameter descriptions and usage rules, in both English (doc/en/source/expert.rst) and Japanese (doc/ja/source/expert.rst) documentation. [1] [2]
• Added documentation for the lattice definition file lattice.def, which is required for Twist operator calculations, including file format and parameter descriptions in both languages. [1] [2]

Output file documentation:

• Updated the output file lists in English and Japanese documentation to include the new xxx_twist_yyy.dat file for Twist operator results. [1] [2]
• Added detailed descriptions of the format and meaning of the data in xxx_twist_yyy.dat in both English and Japanese output documentation. [1] [2]

User rule summaries:

• Updated summary tables in the expert documentation to include Twist operators and lattice definitions, clarifying their role and required input files. [1] [2]
• Added brief descriptions of Twist and lattice input files to the introductory sections of both documentation files. [1] [2]