Refactor theme onto bread-theme; add bakery.toml and release workflow

- Cargo.toml: depend on bread-theme (path dep for local dev, git dep for
  production) with gtk feature; remove local theme dependencies
- src/theme.rs: replace local pywal/Catppuccin impl with bread_theme::gtk
  helpers; local bar-specific CSS is preserved
- bakery.toml: describes breadbar for bakery install
- release.yml: builds on hestia self-hosted runner, publishes binary to
  dl.breadway.dev and GitHub Releases on v* tags

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/bar/clock.rs

@@ -3,7 +3,9 @@ use relm4::ComponentSender;
 
 pub fn current() -> String {
     let dt = gtk4::glib::DateTime::now_local().expect("local time");
-    format!("{:02}:{:02}", dt.hour(), dt.minute())
+    let date = dt.format("%a %d/%m").expect("date format");
+    let time = format!("{:02}:{:02}", dt.hour(), dt.minute());
+    format!("{} {}", date, time)
 }
 
 pub fn spawn_ticker(sender: ComponentSender<App>) {