feat: test prior config + docs for the AdaptPower regularization siblings

[Jammy2211]

Summary

Test prior config, API docs and a composition test for the four *Power regularization siblings added in PyAutoLabs/PyAutoArray#512 (AdaptPower, AdaptSplitPower, AdaptSplitZerothPower, MaternAdaptPowerKernel), through the al.reg namespace.

• test_autolens/config/priors/regularization.yaml gains the four entries, keyed <module>.<Class> as the file's existing entries are, with power fixed as a Constant prior. Verified live: the test config is consulted first, so these entries — not the packaged PyAutoGalaxy ones — are what the suite resolves.
• docs/api/pixelization.rst gains AdaptPower / AdaptSplitPower in the al.reg autosummary.
• test_autolens/test_regularization_power.py mirrors the PyAutoGalaxy composition test.

CI note: green here already. The PyAutoHeart reusable workflow clones each dependency library at the matching branch if it exists, and PyAutoArray#512 uses the same branch name, so this PR's CI tested against it. Library-first merge order still applies for main's sake: merge PyAutoLabs/PyAutoArray#512 first, otherwise main here would reference ag.reg.AdaptPower before the symbol exists.

API Changes

None to autolens source — test config, docs and test additions only. The new public symbols are added upstream in PyAutoLabs/PyAutoArray#512 and reach users here as al.reg.AdaptPower, al.reg.AdaptSplitPower, al.reg.AdaptSplitZerothPower, al.reg.MaternAdaptPowerKernel.
See full details below.

Test Plan

• pytest test_autolens/ — 572 passed, 1 xfailed (with PyAutoArray#512 on PYTHONPATH)
• af.Model(al.reg.AdaptSplitPower) composes; power resolves to the Constant value 1.0 and is absent from the prior tuples
• af.Model(al.reg.AdaptSplit).identifier != af.Model(al.reg.AdaptSplitPower).identifier
• CI green on all four legs (unittest 3.12 / 3.13 / nojax, docs-build), tested against the PyAutoArray branch

Full API Changes (for automation & release notes)

Added

• test_autolens/config/priors/regularization.yaml entries for adapt_power.AdaptPower, adapt_split_power.AdaptSplitPower, adapt_split_zeroth_power.AdaptSplitZerothPower and matern_adapt_power_kernel.MaternAdaptPowerKernel.
• docs/api/pixelization.rst autosummary entries for AdaptPower and AdaptSplitPower.

Migration

• Before: al.reg.AdaptSplit(inner_coefficient=c, outer_coefficient=c)
• After: al.reg.AdaptSplitPower(inner_coefficient=c**2, outer_coefficient=c**2)
• The legacy schemes are untouched, so no migration is required — this is guidance for new work.

Depends on PyAutoLabs/PyAutoArray#512. Refs PyAutoLabs/PyAutoArray#511.

Generated by the PyAutoLabs agent workflow.