Feature/det tar src fb shim

[jackraymond]

Methods are now included for efficient shimming of flux_biases over dimers (one nominal target, one nominal detector) at equilibrium.
The expanded example now shims anneal offsets on targets, as well as flux_biases on target and detectors. I should add anneal offsets on detectors (relative to sources), flux_biases on sources, and approximate mappings from flux_bias perturbations on source/target to (theta,phi).

This pull request builds upon #51
AI was used to create minimal tests.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 87.53994% with 39 lines in your changes missing coverage. Please review.
✅ Project coverage is 92.82%. Comparing base (e86569b) to head (613a65f).
⚠️ Report is 23 commits behind head on main.

Files with missing lines	Patch %	Lines
dwave/experimental/multicolor_anneal/utils.py	86.00%	34 Missing ⚠️
dwave/experimental/shimming/flux_biases.py	92.85%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #58      +/-   ##
==========================================
- Coverage   94.30%   92.82%   -1.49%     
==========================================
  Files          15       15              
  Lines        1141     1449     +308     
==========================================
+ Hits         1076     1345     +269     
- Misses         65      104      +39     

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[jackraymond]

Added detection of source decoupling.
Added ring simulation as a final stage.