feat(borders): use direct2d for anti-aliasing

This commit overhauls the "Komorebi" borders implementation to use
Direct2D, which enables anti-aliasing for rounded borders.

A lot of the heavy lifting was done by @lukeyou05 in the tacky-borders
project, which this commit largely adapts to komorebi. @lukeyou05
provided an incredible amount of guidance and feedback on the
implementation of this feature on the komorebi Discord.

This commit is a squashed interactive rebase of the following commits:

238271a71e
feat(borders): initial impl of direct2d border drawing

5525a382b9
feat(borders): avoid multiple render target creation calls

431970d7b6
feat(borders): reduce redraws to improve perf

47cb19e54a
feat(borders): remove black pixels around direct2d corners

3857d1a46c
feat(borders): clean up render targets on destroy

Cargo.toml

@@ -44,11 +44,15 @@ which = "7"
 version = "0.58"
 features = [
     "implement",
+    "Foundation_Numerics",
     "Win32_System_Com",
     "Win32_UI_Shell_Common", # for IObjectArray
     "Win32_Foundation",
     "Win32_Graphics_Dwm",
     "Win32_Graphics_Gdi",
+    "Win32_Graphics_Direct2D",
+    "Win32_Graphics_Direct2D_Common",
+    "Win32_Graphics_Dxgi_Common",
     "Win32_System_LibraryLoader",
     "Win32_System_RemoteDesktop",
     "Win32_System_Threading",