fix(desktop-environments): missing EWW build dep + non-idempotent clone

Found via a fresh-install test in a QEMU VM using the repo's answerfile
system (hyprlua, tablet/touch eww bar variant).

1. hyprlua.sh/hyprland.sh/niri.sh all compile EWW (GTK3) from source but
   never installed gtk-layer-shell — only gtk4-layer-shell, which is a
   separate package for astal-menu's GTK4 surface. Every fresh install
   failed at the gtk-layer-shell-sys build script with a pkg-config
   error ("gtk-layer-shell-0 ... was not found").

2. The EWW `git clone` isn't idempotent: a leftover ~/install-tmp/eww
   from an earlier interrupted/retried install (e.g. the failure above)
   makes the next clone abort with "already exists and is not an empty
   directory", killing the whole script under set -e. `rm -rf eww`
   before cloning fixes retries.

Both reproduced and fixed directly in the test VM before being applied
here: installing gtk-layer-shell and clearing the stale checkout let
the same run complete successfully.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TLz6HWsXCwzQ97LrLt2em6

setup/modules/Desktop-Environments/hyprland.sh

@@ -141,6 +141,11 @@ HYPRLAND_PACKAGES=(
     playerctl               # MPRIS media player controller (play/pause CLI)
     wf-recorder             # screen recorder for wlroots compositors
     sound-theme-freedesktop # standard freedesktop sound event library
+
+    # EWW (compiled from source below) is GTK3, and its gtk-layer-shell-sys
+    # crate links against this library at build time — without it, `cargo
+    # build` fails at that build script with a pkg-config error.
+    gtk-layer-shell
 )
 sudo pacman -Syu --noconfirm --needed -- "${HYPRLAND_PACKAGES[@]}"
 
@@ -244,6 +249,9 @@ log "Compiling EWW..."
 # ~/install-tmp is a staging area for source trees fetched during installation.
 mkdir -p ~/install-tmp
 cd ~/install-tmp
+# A leftover checkout from an earlier interrupted/retried install would make
+# a plain `git clone` fail with "already exists and is not an empty directory".
+rm -rf eww
 git clone https://github.com/elkowar/eww
 cd eww
 # --release             → optimised binary (significantly faster than debug)

setup/modules/Desktop-Environments/hyprlua.sh

@@ -79,6 +79,12 @@ HYPRLUA_PACKAGES=(
     gtk4                  # GTK4 toolkit (the menu's frontend)
     gtk4-layer-shell      # wlr-layer-shell for GTK4 (the popup surface)
     libshumate            # GTK4 OpenStreetMap widget (Location quad)
+    # EWW itself (compiled from source below) is GTK3, and its
+    # gtk-layer-shell-sys crate links against the GTK3 build of this library —
+    # a separate package from gtk4-layer-shell above. Without it, `cargo build`
+    # fails at the gtk-layer-shell-sys build script with a pkg-config error
+    # ("gtk-layer-shell-0 ... was not found").
+    gtk-layer-shell        # wlr-layer-shell for GTK3 (EWW's build dependency)
     networkmanager        # nmcli backend for the Network quad (adapters/routes/vlan/dns)
     bluez-utils           # bluetoothctl + bluez CLI (Bluetooth quad fallbacks)
     iproute2 curl jq      # ip/ss, HTTP fetches, JSON (Network/Weather backends)
@@ -257,6 +263,9 @@ log "Compiling EWW..."
 # ~/install-tmp is the staging directory for source trees fetched during install.
 mkdir -p ~/install-tmp
 cd ~/install-tmp
+# A leftover checkout from an earlier interrupted/retried install would make
+# a plain `git clone` fail with "already exists and is not an empty directory".
+rm -rf eww
 git clone https://github.com/elkowar/eww
 cd eww
 # --release             → produce an optimised binary (noticeably faster UI)

setup/modules/Desktop-Environments/niri.sh

@@ -27,7 +27,10 @@ sudo pacman -Syu --noconfirm --needed \
     thunar tumbler thunar-archive-plugin thunar-shares-plugin thunar-volman \
     pcmanfm-qt udisks2 ly kew \
     pavucontrol playerctl wf-recorder sound-theme-freedesktop \
-    xinput jq python-opencv v4l-utils
+    xinput jq python-opencv v4l-utils \
+    gtk-layer-shell  # GTK3 wlr-layer-shell library EWW's gtk-layer-shell-sys
+                     # crate links against; without it `cargo build` below
+                     # fails at that build script with a pkg-config error.
 
 # 3. Enable essential services
 log "Enabling essential services..."
@@ -72,6 +75,9 @@ esac
 log "Compiling EWW..."
 mkdir -p ~/install-tmp
 cd ~/install-tmp
+# A leftover checkout from an earlier interrupted/retried install would make
+# a plain `git clone` fail with "already exists and is not an empty directory".
+rm -rf eww
 git clone https://github.com/elkowar/eww
 cd eww
 cargo build --release --no-default-features --features=wayland