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.

docs/config.md

@@ -16,10 +16,12 @@ timeout: 30s           # per backend request
 loadDelay: 150ms       # how long the cursor rests on a row before it loads; 0s loads at once
 sourcesView: grouped   # or flat; ` toggles it
 collapseGroups: true   # start with the Sources pane's groups folded; enter or space unfolds one
-updateCheck: true      # look for a newer release once a day (U and lazysecrets update work either way)
-releases:              # where updates come from, tried in order (GitHub, or a Gitea or Forgejo server)
-  - https://github.com/karleinarb/lazysecrets
-  - https://git.kebcloud.no/keb/lazysecrets
+updates:
+  autoCheck: true          # look for a newer release at startup (U and lazysecrets update work either way)
+  autoCheckInterval: 24h   # at most this often
+  updateSources:           # where updates come from, tried in order (GitHub, or a Gitea or Forgejo server)
+    - https://github.com/karleinarb/lazysecrets
+    - https://git.kebcloud.no/keb/lazysecrets
 history: true          # count uses of items for Recent (R)
 cache: true            # keep what was loaded (never values) for the next start
 providers:
@@ -136,11 +138,12 @@ are read from disk anyway. Deleting the file is always safe, and
 
 ## Updates
 
-Once a day (`updateCheck`), in the background, lazysecrets asks for the
-latest release; within the day it reuses the answer from the state file.
-Releases are published on GitHub and on git.kebcloud.no, and it asks
-them in that order, the next when one doesn't answer within 5 seconds;
-`releases` lists others, such as a mirror of your own. Offline, or with
+At startup, in the background, lazysecrets asks for the latest release
+(`updates.autoCheck`), once a day or every `updates.autoCheckInterval`;
+until then it reuses the answer from the state file. Releases are
+published on GitHub and on git.kebcloud.no, and it asks them in that
+order, the next when one doesn't answer within 5 seconds;
+`updates.updateSources` lists others, such as a mirror of your own. Offline, or with
 every server down, it says nothing. A newer release shows in the footer, `v0.1.1 ↑ v0.2.0`; `U` (or
 `lazysecrets update --check`) shows its changelog.