fix: remove auto-exit timer and smooth cursor tracking

Remove the 10-second display timer so the overlay runs until toggled
off. Shrink the cursor input hole from 512px to 48px for near-pixel-
perfect tracking instead of chunky jumps.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ringa"
-version = "0.1.0"
+version = "0.1.1"
 edition = "2021"
 license = "MIT"
 description = "GPU-rendered ring light overlay for Wayland"