Add centered workspace thumbnails to overview

Render a tinted, scrollable workspace strip with live thumbnails, output-scaled font labels and a subtle selected-workspace outline. Keep the window grid background-free and support workspace selection without exiting overview.

Animate strip opacity independently with precise fade tolerances and continuous reversal, and expose toggle-overview through feresectl.

Cargo.lock

@@ -1570,12 +1570,14 @@ dependencies = [
 name = "ferese"
 version = "0.1.0"
 dependencies = [
+ "ab_glyph",
  "calloop 0.14.4",
  "ferese-animation",
  "ferese-core",
  "ferese-ipc",
  "ferese-layout",
  "ferese-protocols",
+ "fontdb",
  "image",
  "libc",
  "serde",