workspaces: a pill top left on every monitor with its workspaces

- one window per monitor (namespace magic-workspaces, Overlay like the
  island), showing that monitor's hyprland workspaces in the island's
  look: cover gradient, pink glow
- focused workspace pink, shown-elsewhere soft pink, empty ones dim;
  hover eases in (one at a time), a click switches workspace
- special workspaces are skipped; name-only ones show their first letter
- event-driven through Workspaces: redraws only on hyprland events and
  hover

README.md

@@ -11,6 +11,7 @@ A Dynamic-Island-style media widget for Amane (Rust Wayland shell library), runn
 - **Background:** a diagonal gradient from the cover's own colours, darkened so white text stays readable.
 - **Opening animation:** the pill fades out, the empty shape grows, then the card fades in. Closing runs backwards. Moving the pointer off the open card closes it.
 - **Every monitor:** each monitor shows the pill. The card opens only on the monitor you click (a keybind opens it on the focused one), and only the focused monitor's pill shows live bars; the others show still bars, which keeps the cost at about one island's.
+- **Workspace pill:** top left on every monitor, that monitor's Hyprland workspaces as round numbered slots in the island's look. The focused workspace is pink, the one shown on another monitor a softer pink, empty ones dim. Click one to switch to it.
 
 ## Layout
 
@@ -20,6 +21,7 @@ src/island.rs      the view: pill, card, ring, equalizer, dropdowns, animation,
 src/sound.rs       per-player volume, mute, output and equalizer (pactl, pw-cli, pipewire)
 src/spectrum.rs    the shown player's sound as 24 levels (pw-record | cava)
 src/art.rs         cover download (curl) and the palette file
+src/workspaces.rs  the workspace pill, top left on every monitor
 src/parse.rs       pure text parsing with unit tests, no amane dependency
 island-eq          saved equalizer curves (a snapshot of ~/.config/amane/island-eq)
 tools/             remote test driver and fake MPRIS players, see AGENTS.md