Identify “PR process” components that are preventing high-quality contributions

[pllim]

This was mentioned in Astropy Coordination Meeting 2025 breakout ("how to balance all the things").

Also see:

• https://docs.astropy.org/en/latest/index_dev.html
• https://github.com/astropy/astropy-project/blob/main/policies/pull-request-review-and-merge.md
• Pathway from consumer to contributor #448
• Pathway from contributor to maintainer #445