Nothing it carried is gone -- the two commits before this put all of it
somewhere the work is already being done.
A retired destination is the one shape #25's storage decision does not
make free. A visibility entry is a map key and an unknown key is
dropped on load; a launch page is a *value*, and an unknown one fails
validation -- which on the load path means the app refuses to start for
whoever had Jobs selected. `RetiredViews` is that list, read by
`ApplyDefaults`, which treats a retired name as a zero value. An
unknown-but-not-retired name still errors, because that is a typo and
saying so is the useful answer.
The sidebar's eleven entries are more than most libraries need, and
Autotag rewrites tags on disk, which is not what a fresh install should
be one click from.
Stored as a map keyed by view id, where an absent key means that view's
own default. A `HiddenViews []string` cannot express "Autotag off by
default" -- its zero value is *hide nothing* -- and a boolean per view
turns a view that later stops existing into stored garbage. With a map,
an unknown key is dropped on load, a view added later gets its own
default, and no install needs migrating in either direction. Same
polarity as AllowMeteredCatalogDownload: the zero value is the intended
answer.
`Views` is also what DefaultPage now validates against, so which views
exist and which may be the launch page are one list rather than two.
Two states the user could not get out of are refused rather than
allowed: Settings is never hideable, and the launch page is not
hideable while it is the launch page. Both refuse in the *config*, not
in the UI, because `config.toml` is hand-editable. On load the launch
page is instead un-hidden -- there is nobody to tell, and the honest
reading of "my launch page is Autotag" is that this user wants Autotag,
not that their launch page should be silently reset.
logan