* fix(packaging): require macOS 13.4, which the bundled speech engine needs
* fix(updater): keep the macOS requirement title clear of the close button
* fix(packaging): check out the Darwin floor table for adhoc builds and raise the cask floor
* refactor(updater): reuse the parsed Darwin floor for the macOS requirement
* fix(updater): use a margin to keep the macOS requirement title clear of the close button
* fix(updater): say the macOS requirement comes from Electron and the speech engine
darwinVersionForMacos kept only the major of LSMinimumSystemVersion, so a future
15.4 floor would stamp Darwin 24.0.0 and still offer the update to macOS 15.0.
Darwin minors drift from macOS minors, so non-.0 floors now fail the build until
a verified mapping is added.
* Keep dropped-macOS updaters on their last compatible build and explain why
Stamp minimumSystemVersion into every mac update manifest from the built
app's LSMinimumSystemVersion, and refuse to publish an ungated release.
When the updater withholds a newer release for this macOS, show a one-time
notice and say so in Settings and the update card.
* Trim the unsupported-Mac notice copy