CI: migrate release workflow from GitHub Actions to Forgejo Actions

GitHub Actions self-hosted runners need per-repo registration on a
personal account; Forgejo Actions' runner already serves every repo
with zero setup. Moves release publishing there (dl.breadway.dev stays
the primary bakery target; GitHub release upload is kept as the
fallback via an explicit token, since Forgejo Actions has no ambient
GITHUB_TOKEN) and adds a mirror workflow to keep GitHub in sync
automatically.

assets/icons-needed.txt

@@ -0,0 +1,48 @@
+SVG icons needed for breadbar
+==============================
+24×24 viewBox. Use `currentColor` for all fill/stroke so icons recolour
+automatically with the bar theme. Drop finished files in this directory.
+
+
+Control panel — slider row icons
+---------------------------------
+Volume.svg
+    Speaker / soundwave icon for the volume slider row.
+    Currently placeholder: 🔊 emoji label.
+    Usage: control panel, left of volume slider.
+
+Brightness.svg
+    Sun / light bulb icon for the brightness slider row.
+    Currently placeholder: ☀ emoji label.
+    Usage: control panel, left of brightness slider.
+
+
+Power section buttons
+-----------------------
+Lock.svg
+    Padlock icon — triggers hyprlock (lock screen).
+    Currently placeholder: 🔒
+
+Sleep.svg
+    Crescent moon or Zzz icon — triggers systemctl suspend.
+    Currently placeholder: 💤
+
+Restart.svg
+    Circular arrow icon — triggers systemctl reboot.
+    Currently placeholder: 🔄
+
+Shutdown.svg
+    Power symbol (⏻) icon — triggers systemctl poweroff.
+    Currently placeholder: ⏻
+
+
+How to wire up icons once SVGs are ready
+-----------------------------------------
+Each power button and slider row icon is currently a gtk4::Label with an emoji.
+To replace with an SVG:
+
+  1. Add the SVG to this directory.
+  2. In main.rs, replace the emoji Label with:
+       gtk4::Image::from_paintable(Some(&svg_texture(asset!("Icon Name.svg"))))
+  3. For slider rows, replace the icon_lbl in build_slider_row() calls,
+     or add an overload that takes an image widget instead of a string.