docs(api): sync light profile reference with PyAutoGalaxy

[Jammy2211]

Summary

Brings docs/api/light.rst into structural parity with PyAutoGalaxy's equivalent — adds
the previously missing Linear [``ag.lp_linear``], Operated [``ag.lp_operated``], and
Basis [``ag.lp_basis``] autosummary sections, and adds the one-line description to the
Standard section. After this PR the two files are byte-identical.

Motivation: the SersicMultipole / GaussianMultipole profiles merged via #515 (and the
upstream PyAutoGalaxy linear variants) are exposed on al.lp_linear.* but had no API
reference entry on the PyAutoLens docs site. Users browsing the autolens docs could not
discover the linear, operated, basis, or multipole-linear variants from the API page.

Part of #85 on autogalaxy_workspace — this is the library-side prerequisite before the
new scripts/guides/profiles/light.py is added to the two workspaces.

API Changes

None — docs-only change. No Python code is modified, no symbols added or removed. The
new autosummary entries point at classes that already exist in
autogalaxy.profiles.light.* and are already re-exported by autolens as
al.lp_linear, al.lp_operated, al.lp_basis.
See full details below.

Test Plan

• docs/api/light.rst and PyAutoGalaxy/docs/api/light.rst differ by zero bytes
• Existing PyAutoLens unit test suite still passes (no code touched, but pytest is a
  baseline sanity check)
• Optional: Sphinx build of the autolens docs produces no warnings for light.rst

Full API Changes (for automation & release notes)

Added

• docs/api/light.rst Linear section listing the 14 ag.lp_linear profiles documented
  in PyAutoGalaxy (including the newly merged GaussianMultipole and SersicMultipole
  linear variants)
• docs/api/light.rst Operated section listing ag.lp_operated.Gaussian, Moffat, Sersic
• docs/api/light.rst Basis section listing ag.lp_basis.Basis
• One-line description to the existing Standard section for consistency with PyAutoGalaxy

Removed

• None

Renamed

• None

Changed Signature

• None

Changed Behaviour

• None

Migration

• None — purely additive docs change. No user-facing API affected.

🤖 Generated with Claude Code

[Jammy2211]

Workspace PR: PyAutoLabs/autogalaxy_workspace#86

[Jammy2211]

Workspace PR: PyAutoLabs/autolens_workspace#176