Restructure packages into per-program home/programs/ modules

Replaces the monolithic packages-marvin.nix with one file per program
so hosts can opt in selectively. Adds docker, clamav, steam, and
audio keybindings for hivebrain. Fixes monitor order and switches
volume widget to PulseVolume.

config/qtile/config.py

@@ -60,6 +60,9 @@ keys = [
         lazy.spawn('sh -c "maim -s | xclip -selection clipboard -t image/png -i"'),
         desc="Screenshot"
     ),
+    Key([mod], "F6", lazy.spawn("wpctl set-volume -l 1.0 @DEFAULT_AUDIO_SINK@ 5%+"), desc="Volume up 5%"),
+    Key([mod], "F5", lazy.spawn("wpctl set-volume @DEFAULT_AUDIO_SINK@ 5%-"), desc="Volume down 5%"),
+    Key([mod], "F4", lazy.spawn("wpctl set-mute @DEFAULT_AUDIO_SINK@ toggle"), desc="Mute toggle"),
 ]
 
 # Add key bindings to switch VTs in Wayland.
@@ -229,7 +232,7 @@ def make_top_bar(primary=False):
             format = 'Mem: {MemUsed:.0f}{mm}',
         ),
         make_sep(),
-        widget.Volume(
+        widget.PulseVolume(
             foreground = colors[7],
             padding = 8,
             fmt = 'Vol: {}',
@@ -249,8 +252,8 @@ def make_top_bar(primary=False):
 
 
 screens = [
-    Screen(top = make_top_bar()),
     Screen(top = make_top_bar(primary=True)),
+    Screen(top = make_top_bar()),
 ]
 
 # Drag floating layouts.