fix(waybar): drop the bar to the bottom layer so fullscreen covers it

On Hyprland the `top` layer renders above every window, including a real
fullscreen surface — so a browser video gone fullscreen sat *under* the
bar (BACKLOG item 30). Move the bar to `layer: bottom` in the generated
waybar.nix and all four whole-swap jsoncs (parity rule); the exclusive
zone still reserves its space in normal tiling, but a fullscreen window
now covers it. Rationale comment kept in waybar.nix; data jsoncs left
comment-free (they carry none).

Verified: V0 (nix flake check --no-build, green) + V1
(homeConfigurations.nomarchy.activationPackage builds; built
.config/waybar/config shows "layer": "bottom"). V3 queued in
HARDWARE-QUEUE (fullscreen covers bar + returns on exit; floating-overlap
trade-off).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agent/MEMORY.md

@@ -63,6 +63,11 @@ iteration would otherwise rediscover.
   split (BACKLOG LATER) is the decided fix (§ Faster switches).
 
 ## Gotchas (cost a debugging session once)
+- Waybar `layer: top` renders above **even real-fullscreen windows** — the
+  bar draws over a fullscreen video. `layer: bottom` lets the fullscreen
+  surface cover it while the exclusive zone still reserves the bar's space
+  in normal tiling (trade-off: floating windows can now overlap the bar
+  strip). Set in both waybar.nix and every whole-swap jsonc (item 30).
 - Hyprland binds match the exact modmask: a shifted keysym (`question`)
   needs SHIFT in `mods` or the bind never fires — the keypress falls
   through to the focused window (§ item 26; caught on hardware, invisible