Makie bloch sphere extension

[Aniket-umass]

This PR introduces a new Makie-based Bloch sphere visualization extension for QuantumOpticsBase.

Features:

• blochsphere(state::Ket) renders the Bloch sphere for any spin-1/2 quantum state.
• The Bloch vector is calculated directly from the Ket input.
• Supports CairoMakie and GLMakie backends.
• Sphere and arrows fully represent the quantum state.
• Project.toml updated to include Makie as a weak dependency and an extension.

Testing:

• Example: ( in julia )

using QuantumOpticsBase
using CairoMakie
include("ext/QuantumOpticsBaseMakieExt.jl")
using .QuantumOpticsBaseMakieExt
b = SpinBasis(1//2)
state = spinup(b)
f = blochsphere(state)

[Krastanov]

Thanks, this is a good start!

Check the comments I left in.

A few other things:

• this new functionality needs tests (check PBCCompiler.jl for an example of how to structure the tests)
• and it needs docs
• for ease of review, it would be helpful to post in the comments what a rendering looks like so we can discuss it before a full in-depth review.

[Krastanov]

include("ext/QuantumOpticsBaseMakieExt.jl")

You should not include extensions manually. They are supposed to be loaded when the library is imported together with the weakdeps for the extension. Check out the details in the Pkg.jl manual.