feat: remove fit_quick.png — quick updates write the normal fit subplot

[Jammy2211]

Summary

Closes #680. Quick updates during a non-linear search previously wrote a special lighter-weight fit_quick.png for every PyAutoLens dataset type, so the user had to visually recognise two different fit-plot layouts for the same fit. The quick_update=True path in the four model plotters (imaging, interferometer, point, weak) now writes the normal fit subplot and returns, still skipping the heavy extras (log10 / planes / tracer / dirty-image variants / FITS). The five quick figure functions are deleted. PyAutoGalaxy already behaved this way; companion PyAutoFit PR reduces the live-display candidate list to fit.png.

API Changes

Quick updates now write the normal fit subplot file (fit.png for imaging/interferometer/point, subplot_fit_weak.png for weak) instead of fit_quick.png; the module-level quick figure functions are removed (none were exported in the aplt namespace). See full details below.

Test Plan

• test_autolens/ full suite: 498 passed
• Branch merged with origin/main (includes Point-source phase A: PairAll log-sum-exp stabilization + free-centre tensor option #679) before push; no conflicts
• Follow-up workspace PR updates the three autolens_workspace_test visualization-jit scripts that assert fit_quick.png

Full API Changes (for automation & release notes)

Removed

• autolens.imaging.plot.fit_imaging_plots.subplot_fit_quick — quick path now calls subplot_fit (plain fit.png, final plane as source, any plane count)
• autolens.imaging.plot.fit_imaging_plots.subplot_fit_combined_quick — had no callers
• autolens.interferometer.plot.fit_interferometer_plots.subplot_fit_quick — quick path now calls subplot_fit
• autolens.point.plot.fit_point_plots.subplot_fit_quick — quick path now calls subplot_fit (with critical-curve overlays)
• autolens.weak.plot.fit_weak_plots.subplot_fit_quick — quick path now calls subplot_fit_weak

None of these were exported via autolens.plot (aplt) or the aggregator.

Changed Behaviour

• PlotterImaging.fit_imaging(quick_update=True) — writes the normal 12-panel fit.png (single normal subplot even for >2-plane tracers, so the live display always has one canonical filename)
• PlotterInterferometer.fit_interferometer(quick_update=True) — always writes the normal fit.png, then returns before tracer/dirty/real-space extras
• PlotterPoint.fit_point(quick_update=True) — writes the normal fit.png including critical-curve/caustic overlays
• PlotterWeak.fit_weak(quick_update=True) — writes the normal subplot_fit_weak.png (note: the live viewer only resolves fit.png, so weak fits no longer surface in the live display — pre-existing filename quirk of the weak module)
• Output directories no longer contain fit_quick.png

Migration

• Before: monitor fit_quick.png for search progress
• After: monitor fit.png (the same file the full visualization writes)

Shipped under human-authorized Heart-RED override; RED reason (verbatim, unrelated nightly): release validation FAILED (stage integrate).

Generated by the PyAutoLabs agent workflow.

[Jammy2211]

Added quick_update=True routing tests for all four model plotters (368f928) — each asserts the normal fit subplot is written, fit_quick.png is not, and the heavy extras are skipped. End-to-end validation: the autolens_workspace_test imaging visualization-jit script ran under this branch — the quick update fired and wrote fit.png (no fit_quick.png); the run was later OOM-killed in the unrelated end-of-search latent-samples phase under concurrent machine load, and its only earlier failure was a pre-existing Part 1 timing-flake assertion (107 ms vs 100 ms threshold on WSL).

[Jammy2211]

Workspace follow-up PR: PyAutoLabs/autolens_workspace_test#241 (merge this library PR first — library-first gate).