Add derivative for GuidedAmplitude

[goerz]

Followup to JuliaQuantumControl/QuantumPropagators.jl#111

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.7%. Comparing base (1ece6f0) to head (07998cc).

Additional details and impacted files

@@           Coverage Diff            @@
##           master    #107     +/-   ##
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+ Coverage    87.7%   87.7%   +0.1%     
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  Files          20      20             
  Lines        1123    1124      +1     
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+ Hits          984     985      +1     
  Misses        139     139             

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[Copilot]

Pull request overview

Adds get_control_deriv support for QuantumPropagators.Amplitudes.GuidedAmplitude so gradient/derivative extraction works consistently across amplitude types, following the upstream QuantumPropagators.jl changes.

Changes:

• Add get_control_deriv(::GuidedAmplitude, control) returning LockedAmplitude(shape) for the matching control.
• Extend derivative tests to cover GuidedAmplitude, including the discretized-on-tlist constructor case.
• Tighten/import adjustments in the derivative test file to use specific QuantumPropagators.Controls symbols.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/derivs.jl	Implements get_control_deriv method for GuidedAmplitude consistent with ShapedAmplitude.
test/test_derivs.jl	Adds a dedicated testset validating GuidedAmplitude derivatives for functional and discretized controls.

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