[Dependency] Electronic state `source_estate` depending back on the method layer

[Critsium-xy]

Describe the Code Quality Issue

• Symptom: estate directly includes concrete basis implementations (dftu.h, spin_constrain.h, gint, module_rt, structure_factor.h, vnl_pw.h, parallel_grid.h, …), while lcao→estate and pw→estate also hold — a large bidirectional cycle.
• Fix: push "how to compute density/potential under a given basis" down into the method layer — pw/lcao each derive an ElecState subclass; estate keeps only the base class and shared logic. The direction converges to one-way pw/lcao → estate.
• Acceptance: cut estate → pw/lcao.

Additional Context

No response

Task list for Issue attackers (only for developers)

• Identify the specific code file or section with the code quality issue.
• Investigate the issue and determine the root cause.
• Research best practices and potential solutions for the identified issue.
• Refactor the code to improve code quality, following the suggested solution.
• Ensure the refactored code adheres to the project's coding standards.
• Test the refactored code to ensure it functions as expected.
• Update any relevant documentation, if necessary.
• Submit a pull request with the refactored code and a description of the changes made.