docs: document hypridle, correct stale swww->awww references

Adds the hypridle entry to ARCHITECTURE, and folds in the pending
swww->awww wallpaper-tool rename in ARCHITECTURE + README (the repo spawns
awww-daemon, not swww).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ARCHITECTURE.md

@@ -129,13 +129,20 @@ This system is a **Wayland-first desktop environment** built around the **Niri c
 * Native fprintd polling — touch the reader to unlock without typing
 * Blurred-screenshot background, Tomorrow Night palette
 
+#### hypridle
+
+* Idle daemon paired with hyprlock (replaces swayidle)
+* Honors idle inhibitors, so video/calls no longer blank or lock the screen
+* Stages: blank monitors @ 5 min → lock @ 10 min → suspend-then-hibernate @ 30 min
+* Locks via `loginctl lock-session` so logind-driven locks (e.g. before sleep) stay deduplicated
+
 ---
 
 ### Background Services
 
 | Function    | Tool                 |
 | ----------- | -------------------- |
-| Wallpaper   | swww                 |
+| Wallpaper   | awww                 |
 | Screenshots | grim + slurp + satty |
 | Clipboard   | cliphist             |
 
@@ -152,7 +159,7 @@ This system is a **Wayland-first desktop environment** built around the **Niri c
 
    * waybar
    * mako
-   * swww
+   * awww (awww-daemon; restores last wallpaper from cache)
    * cliphist (if enabled)
 
 ---