Add 6 desktop features: workspace shortcuts, Exposé, deskbar icons, notifications, screen lock, move-to-desktop

- Super+1-4: switch virtual desktop; Super+Shift+1-4: move focused window to desktop N
- Super+Space: Exposé window overview (tiled grid), click to select, Escape to cancel
- wm/src/expose.c: expose_show/expose_hide using ceil(sqrt) grid layout with saved/restored geometry
- client_move_to_desktop(): moves window between desktops, fires _NET_WM_DESKTOP update
- on_client_message: handles _NET_WM_DESKTOP to move windows from external requests
- deskbar: optional imlib2 app icon rendering (Papirus-Dark → Papirus → hicolor → pixmaps fallback)
- deskbar: XGetClassHint populates cls field for better icon lookup
- deskbar: context menu extended with separator + "→ Desktop 1-4" items via _NET_WM_DESKTOP
- orionnotify/: freedesktop.org notification daemon (libdbus-1), stacks up to 5 popups top-right
- orionlock/: PAM-authenticated fullscreen screen lock with clock, date, password dots
- Lock Screen menu item wired to orionlock
- Root Makefile includes orionnotify and orionlock targets

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GHiBQKPfUoaJgCKuA9op1H

Makefile

@@ -5,9 +5,9 @@
 #   make clean    — remove build artifacts
 #   make iso      — build the bootable ISO (requires Arch Linux + archiso)
 
-.PHONY: all wm deskbar launcher installer nebula orionpkg skykit rigel quill lens clean install iso
+.PHONY: all wm deskbar launcher installer nebula orionpkg skykit rigel quill lens orionnotify orionlock clean install iso
 
-all: wm deskbar launcher installer nebula orionpkg skykit rigel quill lens
+all: wm deskbar launcher installer nebula orionpkg skykit rigel quill lens orionnotify orionlock
 
 wm:
 	$(MAKE) -C wm
@@ -39,6 +39,12 @@ quill:
 lens:
 	$(MAKE) -C lens
 
+orionnotify:
+	$(MAKE) -C orionnotify
+
+orionlock:
+	$(MAKE) -C orionlock
+
 clean:
 	$(MAKE) -C wm        clean
 	$(MAKE) -C deskbar   clean
@@ -49,7 +55,9 @@ clean:
 	$(MAKE) -C skykit    clean
 	$(MAKE) -C rigel     clean
 	$(MAKE) -C quill     clean
-	$(MAKE) -C lens      clean
+	$(MAKE) -C lens         clean
+	$(MAKE) -C orionnotify  clean
+	$(MAKE) -C orionlock    clean
 
 install: all
 	# binaries
@@ -62,6 +70,8 @@ install: all
 	install -Dm755 rigel/rigel             /usr/local/bin/rigel
 	install -Dm755 quill/quill             /usr/local/bin/quill
 	install -Dm755 lens/lens               /usr/local/bin/lens
+	install -Dm755 orionnotify/orionnotify /usr/local/bin/orionnotify
+	install -Dm755 orionlock/orionlock     /usr/local/bin/orionlock
 	# GTK theme
 	mkdir -p /usr/share/themes
 	cp -r themes/OrionOS /usr/share/themes/
@@ -77,6 +87,7 @@ install: all
 	@echo "  orionwallpaper"
 	@echo "  picom --config /etc/orionos/picom.conf &"
 	@echo "  oriondeskbar &"
+	@echo "  orionnotify &"
 	@echo "  exec orionwm"
 
 iso: