<!-- Title: what knotless does once this lands, as main's log reads:
     "Deploys roll serve and pages over with no downtime". At most 72
     characters, an optional crate prefix ("knotless-run: …"), no
     period, never only the activity ("Fix bug", "Update serve").
     The squash commit takes this title and body as its message, so
     say everything here: a link is no substitute for the reason.
     Delete a section that has nothing to say, but keep at least one:
     a body with none of these headings is refused.
     Name a pull or issue of this repository by its at:// URI, bare,
     not in `code`: its page shows it as a link with its title, and an
     issue named so lists this pull on its own page. -->

## What changes

<!-- What someone using knotless, or reading the code, finds different.
     One bold-led paragraph per part when there are several. -->

## Why

<!-- The problem, and why this way over the others considered.
     "Fixes <issue's page or at:// URI>" closes it as this merges; say
     what it was all the same. -->

## How it was checked

<!-- Tests added or run, scenarios, shots. What is left to CI. Pages
     this moves on purpose are named on a line of their own, which the
     shots check reads: "Shots-moved: home, pull-open" (or "all"). -->

## Shortcomings

<!-- What it does not do, what was not run, what could go wrong. -->

## Review

<!-- Optional: the kind of review wanted (a quick look, the design,
     one risky part) and where to start reading. -->