Add edep tally and update neutron functions

[melekderman]

This pull request introduces support for tallying energy deposition ("edep") in mesh tallies. It adds the new "edep" score type, implements the logic for calculating energy deposition during neutron collisions, and ensures that energy deposition is only tallied in valid scenarios. The changes also include the necessary infrastructure to score and accumulate energy deposition results in mesh tallies.

Support for energy deposition ("edep") tallying:

• Added new score type SCORE_EDEP for energy deposition to constant.py, and integrated it into the tally score system in tally.py and related modules. [1] [2] [3] [4] [5]
• Restricted the use of the "edep" score to mesh tallies only and disallowed its combination with the "energy" multiplier.

Implementation of energy deposition calculation:

• Refactored the neutron collision process to compute and return the energy deposited (edep_weighted) during each collision, including contributions from implicit capture, elastic/inelastic scattering, and fission. Updated the respective scattering and fission routines to return the appropriate weighted energy output for tallying. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15]

Scoring and tallying infrastructure:

• Implemented the mesh_tally_edep function in score.py to accumulate energy deposition scores in mesh tallies, including phase-space and mesh bin checks.
• Updated the simulation loop to call mesh_tally_edep after each collision when appropriate.

[ilhamv]

As discussed, the plan is to wait for the merge of #385, which reorganizes tally types by the estimator (tracklength, surface-crossing, and collision). The edep in this PR uses the collision estimator.