Add hamiltonian functions

[TejaashriUK]

Fixes #13235

Describe your change:

• Add an algorithm?

This PR adds physics/hamiltonian.py, which implements two functions requested in #13235:

1. classical_hamiltonian(mass, velocity, potential_energy) — computes the classical Hamiltonian H = T + V, where kinetic energy T = 0.5 * m * v^2.
2. quantum_hamiltonian(num_points, potential, mass, hbar, dx) — constructs the Hamiltonian matrix for a particle in a 1D potential using finite-difference discretization of the time-independent Schrödinger equation.

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".