release: 1.8.20

[florianmousseau]

Stamps [Unreleased] as 1.8.20 and bumps package.json. Four entries, none
of which moves anything an app already relies on, so a patch.

The duplicate ### Added headings the separate feature PRs left behind are
merged into one section per type while stamping.

What ships

• One register function per widget, so an app stops shipping the widgets it
  never renders. The barrel names all nine elements, which is what pins them in
  a bundle: a status line went from 101.5 kB to 5.1 kB.
• Four accessibility defects, each measured: two default severity colors
  failed AA as text (3.30:1 and 3.19:1, now 5.02:1), the blocking gate declared
  itself modal without holding the keyboard, no widget had a live region, and
  the spinner ignored prefers-reduced-motion.
• exportBackup({ plaintext: true }): a readable copy of a protected store,
  where the only route before was unprotect() - which rewrites the destination
  and leaves the real backup unencrypted until someone undoes it.
• A budget on what one edit costs to save, in bytes rather than
  milliseconds: 19 kB at 1 000 records, 163 kB at 10 000.

Cadence

First release since 1.8.19 yesterday, and the entries were allowed to
accumulate rather than shipping one per merge. That is the behaviour
RELEASING.md asks for, and it is worth noting because the previous days did not
manage it.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[florianmousseau]

Superseded by #105: another session stamped 1.8.20 first, with the same four entries and the same grouping. Nothing to add.