docs: 2.3.3 release notes, diagram_theme setting, amber renamed-FK edges

[dimitri-yatsenko]

Documentation for the 2.3.3 release, being tagged today. Independent of the tag itself — this can land before or after.

What

## Changes in 2.3.3 in whats-new-23.md — a bullet per user-visible change, in the established shape of the 2.3.1 and 2.3.2 sections. The one worth reading closely is the s3 bullet: access_key/secret_key becoming optional is what unblocks running under an assumed role with no long-lived keys, and it is the reason this release is being cut now.

display.diagram_theme in reference/configuration.md — this setting arrived with the brand-palette work in datajoint-python#1544 and was documented nowhere. It takes auto (default), light, or dark, and reads DJ_DIAGRAM_THEME.

The renamed-foreign-key edge is amber, not orange. Two things changed in the restyle and the docs tracked neither:

	before	now
Renamed FK edge	#FF8800 — true orange	#C77D3A — amber
Computed tier stroke	red-ish	#FF5113 — brand orange

So "orange edges = renamed FK" now names the same color as the Computed tier, and the read-diagrams notation legend still said Red=Computed. Both are wrong and they are wrong in a way that makes the legend self-contradicting. The renamed-edge wording moves to "amber" consistently across read-diagrams.ipynb (the section heading and four prose spots), model-relationships.ipynb, 02-schema-design.ipynb, and the notation spec in reference/specs/diagram.md, where the entry now carries the hex and says explicitly that it is distinct from the Computed tier above it.

Note the many other "orange" mentions in the docs — the domain tutorials, relational-workflow-model.md, the tier table in diagram.md — were already correct and are untouched. Those refer to Computed ellipses, which really are orange.

Scope

Markdown cells only. No notebook was re-executed, so the diff carries no output churn — please confirm that reads true in the notebook diffs.

Known gap, not fixed here: the embedded diagram figures in these notebooks were last rendered 2026-08-13, before datajoint-python#1544 and datajoint-python#1545 landed, so they still show the pre-brand colors. The prose now describes the palette correctly and the pictures do not yet match it. Regenerating them needs a live database and is better done against released 2.3.3 — tracked by #266. src/llms-full.txt is stale for the same reason (generated 2026-07-17 from release/docs-2.3.1) and can be regenerated by scripts/gen_llms_full.py in that same pass.

mkdocs.yaml's datajoint_version deliberately stays "2.3" — it marks the minor line, not the patch.

Checks

• All five relative links in the new section resolve, including the #display-settings anchor.
• All three edited notebooks still parse as JSON; scripts/check_notebook_versions.py passes.