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

bakery.toml

@@ -0,0 +1,11 @@
+name = "breadbar"
+description = "Minimal status bar and notification daemon for Hyprland"
+binaries = ["breadbar"]
+system_deps = ["gtk4", "gtk4-layer-shell", "iw"]
+bread_deps = []
+
+[config]
+dir = "~/.config/breadbar"
+
+[install]
+post_install = []