refactor(fastfetch): merge the mac and kde configs into common

One Fastfetch package now serves both platforms. The logo is sent
inline through the kitty graphics protocol from a pre-encoded
albedo.kitty, which works in Ghostty and Kwi alike, so the separate
kitty-direct (mac) and Konsole (kde) variants are no longer needed.

common/fastfetch/.stow-local-ignore

@@ -0,0 +1,3 @@
+^/README.*
+^/build\.py
+__pycache__