fix(sway): visible focus ring, floating modifier, volume binds

swayfx: with `border pixel` the visible line is child_border, not `border`
(which only paints title bars). Focused child_border was $base00 = black on
black, i.e. invisible; both are now the same gray.

keybinds: restore `floating_modifier $mod normal` (was `none`) and drop the
`pkill -RTMIN+10 i3blocks` tail from the volume binds -- i3blocks is not in
use, waybar is.

windows: drop a stray trailing semicolon; waybar: remove the unused
sway/submap module.

.config/sway/waybar/config.jsonc

@@ -3,7 +3,6 @@
     "spacing": 2, // Gaps between modules (4px)
     "modules-left": [
         "sway/workspaces",
-        "sway/submap",
         "sway/scratchpad",
         "sway/window"
     ],