Add visibility forward fitting

[samaloney]

Implement vis forward fit with scipy minimise, defaulting to Nelder-Mead for now would be interesting to compare and contrast other method on simulate dataset/real dataset

• Add basic implementation
• Add PSO
• Add elliptical and loop sources?
• More tests
• Create image from source list
• Map wrapper
• Test on real data
• Add ability to fix, vary, tie parameters (maybe astropy modelling?) separated out in Add model parameters handling e.g fix, vary, bounds (using astropy modeling or something else) #89

Closes #84

[codecov]

Codecov Report

❌ Patch coverage is 78.33333% with 52 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@0ad20f2). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
xrayvision/visualisation.py	23.80%	32 Missing ⚠️
xrayvision/vis_forward_fit/forward_fit.py	84.21%	12 Missing ⚠️
xrayvision/vis_forward_fit/sources.py	93.96%	7 Missing ⚠️
xrayvision/visibility.py	66.66%	1 Missing ⚠️

Additional details and impacted files

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##             main      #83   +/-   ##
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  Coverage        ?   87.12%           
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  Files           ?       12           
  Lines           ?     1188           
  Branches        ?        0           
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  Hits            ?     1035           
  Misses          ?      153           
  Partials        ?        0           

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[Copilot]

Pull Request Overview

This PR adds visibility forward fitting functionality with support for both Nelder-Mead and particle swarm optimization (PSO) methods. It introduces parametric source models (circular and elliptical Gaussians) for fitting solar features to visibility data.

• Add new vis_forward_fit module with source definitions and fitting algorithms
• Implement both scipy minimization and PSO fitting methods for optimization
• Create visualization utilities for plotting visibilities

Reviewed Changes

Copilot reviewed 23 out of 25 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
xrayvision/vis_forward_fit/sources.py	Defines parametric source models (circular/elliptical Gaussians) and factory classes
xrayvision/vis_forward_fit/forward_fit.py	Implements forward fitting algorithms using scipy minimize and PSO
xrayvision/visualisation.py	Adds visibility plotting functions for amplitude/phase visualization
xrayvision/vis_forward_fit/tests/	Test files for source models and fitting functionality
examples/stix.py	Updates example to demonstrate new forward fitting capabilities

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[Copilot]

Copy-paste error in bounds definition. The second element should use self.y0 not self.x0 for the y-coordinate bound.

Suggested change

	[self.amp / 4, self.x0 - 5 * np.abs(self.sigma), self.x0 - 5 * np.abs(self.sigma), self.sigma / 4],
	[self.amp * 4, self.x0 + 5 * np.abs(self.sigma), self.x0 + 5 * np.abs(self.sigma), self.sigma * 4],
	[self.amp / 4, self.x0 - 5 * np.abs(self.sigma), self.y0 - 5 * np.abs(self.sigma), self.sigma / 4],
	[self.amp * 4, self.x0 + 5 * np.abs(self.sigma), self.y0 + 5 * np.abs(self.sigma), self.sigma * 4],

[Copilot]

Return type inconsistent with docstring. The function docstring indicates it returns Figure but the code returns tuple[Figure, list].