docs,ui: low vram guide & first run blurb

[psychedelicious]

Summary

• Fix minor issue in the configuration docs.
• Add docs for low-VRAM mode, with links to the new page in the Features and Configuration sections.
• Update the first run screen to include a link to the docs:

QA Instructions

Build the docs locally to preview.

Checklist

• The PR has a short but descriptive title, suitable for a changelog
• Documentation added / updated (if applicable)

[RyanJDick]

Excellent docs. I just suggested one nit-pick.

[psychedelicious]

Updated first run page (Low VRAM callout only rendered on Local):

OOM toast (local only):

(the minor vertical alignment issue w/ the links is fixed, just didn't capture it in screenshots)