Improve niri config

dot_config/niri/config.kdl

···
     // ─── Applications ───
     MOD+RETURN                          hotkey-overlay-title="Open Terminal: alacritty" { spawn-sh "alacritty"; }
     MOD+SPACE                           hotkey-overlay-title="Open App Launcher: wofi" { spawn-sh "wofi"; }
-    MOD+B                               hotkey-overlay-title="Open Browser: zen" { spawn-sh "zen-browser"; }
+    MOD+B                               hotkey-overlay-title="Open Brave" { spawn-sh "brave"; }
+    MOD+N                               hotkey-overlay-title="Open Obsidian" { spawn-sh "obsidian"; }
+    MOD+A                               hotkey-overlay-title="Open Activities: btop" { spawn-sh "alacritty -e btop"; }
     MOD+ALT+L                           hotkey-overlay-title="Lock Screen: loginctl" { spawn-sh "loginctl lock-session"; }
     
     // Please choose your own file manager
···
 // https://github.com/YaLTeR/niri/wiki/Configuration:-Window-Rules
 
     window-rule {
-        match app-id=r#"zen-browser$"# title="^Picture-in-Picture$"
-        open-floating true // Always float Firefox PiP windows
-    }
-
-    window-rule {
-        geometry-corner-radius 20 // Set every window radius to 20
+        geometry-corner-radius 7
         clip-to-geometry true
     }