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/types/src/display.rs

@@ -94,6 +94,24 @@ pub mod window {
     /// From init (unbadged) only: word 1 a launcher's badge, which has
     /// gone; every window it opened closes.
     pub const FORGET: usize = 8;
+    /// Through a window: word 1 a part (0 to `THEME_WORDS / 2 - 1`) of
+    /// the theme in use, as `theme::wire` words it. Reply `[OK, changes |
+    /// index << 32, word, word]`: `changes` counts switches (a client that
+    /// sees it move mid-read starts over); `index` is the theme's place in
+    /// `THEME_NAME`'s list.
+    pub const THEME: usize = 9;
+    pub const THEME_WORDS: usize = 8;
+    /// Through a window: word 1 an index. Reply `[OK, name]` (`pack_name`)
+    /// for each theme the display has, `MALFORMED` past the last.
+    pub const THEME_NAME: usize = 10;
+    /// From init (unbadged) only: the theme named in words 1..4 (empty:
+    /// the default) is now in use; `MALFORMED` if there is none by that
+    /// name.
+    pub const SET_THEME: usize = 11;
+    /// The event (in place of an input event's tag) every window gets when
+    /// the theme changes: ask for it again.
+    pub const THEME_CHANGED: usize = 16;
+
     /// The function key that brings the next window to the front; the
     /// display keeps it to itself.
     pub const SWITCH_KEY: usize = 1;

crates/types/src/spawn.rs

@@ -23,6 +23,10 @@ pub const SIGN_OUT: usize = 1;
 /// Through the same copy: who is signed in. Reply `[role, name...]`, the
 /// name in three words (`types::name`); role as in `role`.
 pub const WHO: usize = 2;
+/// Through the same copy: the signed-in user's theme is now the one named
+/// in words 1..4 (`types::name`; empty: the default). Kept in their folder
+/// and shown at once. Reply `[OK, ..]`, or `MALFORMED`.
+pub const SET_THEME: usize = 3;
 
 pub mod role {
     pub const OWNER: usize = 1;