feat(theme): themes as files (theme crate: toml subset + ints, contrast check, wire); whimsy dark + light; display reads themes/, serves THEME/THEME_NAME, init SET_THEME -> THEME_CHANGED to all windows, bar themed; k-ui follows; settings appearance; init keeps choice in sealed users/<id>/settings/, reapplies at sign-in + display restart

crates/servers/storage-server/src/encrypted.rs

@@ -1,6 +1,7 @@
 //! The encrypted areas (see the vision's Encryption and Users notes), over
 //! any file system. Each user's folder `users/<id>/` holds their areas:
-//! `home/`, `permissions/`, and per app `apps/<app>/` and `data/<app>/`,
+//! `home/`, `permissions/`, `settings/` (init's record of their choices,
+//! such as the theme), and per app `apps/<app>/` and `data/<app>/`,
 //! each kept as `filecrypt` files under its own key, derived from that
 //! user's master key. Only the signed-in user's areas open; anyone else's
 //! are refused (and noise to their key anyway). The rest (programs,
@@ -42,7 +43,7 @@ fn area(path: &[u8]) -> (Area<'_>, Option<&[u8]>) {
     let upto = |n: usize| &path[..n];
     let base = 6 + user.len() + 1;
     let area = match (kind, app, rest) {
-        (Some(k @ (b"home" | b"permissions")), _, _) => Area::Sealed(upto(base + k.len())),
+        (Some(k @ (b"home" | b"permissions" | b"settings")), _, _) => Area::Sealed(upto(base + k.len())),
         (Some(k @ (b"apps" | b"data")), Some(a), Some(r)) if !a.is_empty() && !r.is_empty() => Area::Sealed(upto(base + k.len() + 1 + a.len())),
         _ => Area::Neither,
     };