Add manifest.diagram to the pipeline template, with linting - #4460

The base and head of this comparison were measured with different runner settings, so their benchmark values are not directly comparable.

What changed between base and head:

• CodSpeed runner v5 changed how benchmarks are measured (base 4.18.4 → head 5.0.1). View release notes

Re-run the base with the same settings to get a valid performance comparison.

_{Comparing ewels:manifest-diagram (e7cea70) with dev (cb0ac11)¹}