feat: update settings move under updates, with an interval

updates.autoCheck (was updateCheck) and updates.updateSources (was
releases) sit together with updates.autoCheckInterval, a duration (24h
by default) for how often lazysecrets looks for a newer release on its
own.

internal/ui/app/app.go

@@ -117,9 +117,11 @@ type Options struct {
 	// Keys, if set, replaces the default keymap (keys.Map.Apply).
 	Keys *keys.Map
 	// Updater, if set, finds and installs newer releases (U); with
-	// UpdateCheck, lazysecrets also looks once a day on its own.
+	// UpdateCheck, lazysecrets also looks on its own at startup, at most
+	// once per UpdateEvery (0 for a day).
 	Updater     *Updater
 	UpdateCheck bool
+	UpdateEvery time.Duration
 	// HandlerSetup, if set, offers to set up the link handler at startup.
 	HandlerSetup *HandlerSetup
 	// NoHistory stops counting uses of items for the Recent list.
@@ -236,6 +238,7 @@ type Model struct {
 
 	updater      *Updater
 	updateCheck  bool
+	updateEvery  time.Duration
 	fetchOnStart bool            // look for a newer release in Init
 	newer        *update.Release // a newer release to offer
 	updated      string          // the release installed, waiting for a restart
@@ -427,7 +430,10 @@ func New(providers []provider.Provider, opts Options) Model {
 	m.revealTimeout, m.hideOnBlur = opts.RevealTimeout, opts.HideOnBlur
 	m.expiryWarning = opts.ExpiryWarning
 	m.handlerSetup = opts.HandlerSetup
-	m.updater, m.updateCheck = opts.Updater, opts.UpdateCheck
+	m.updater, m.updateCheck, m.updateEvery = opts.Updater, opts.UpdateCheck, opts.UpdateEvery
+	if m.updateEvery == 0 {
+		m.updateEvery = updateEvery
+	}
 	m.startUpdateCheck()
 	m.askHandler = opts.HandlerSetup != nil && !m.store.Flag(flagNoHandlerPrompt)
 	m.settle = opts.LoadDelay