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

wm/src/events.c

@@ -74,6 +74,7 @@ void on_expose(WM *wm, XExposeEvent *e) {
     if (c && !c->minimized) frame_draw(wm, c);
 }
 
+
 void on_configure_request(WM *wm, XConfigureRequestEvent *e) {
     Client *c = client_find_by_win(wm, e->window);
     XWindowChanges wc;
@@ -136,6 +137,7 @@ void on_client_message(WM *wm, XClientMessageEvent *e) {
     Atom net_active       = XInternAtom(wm->dpy, "_NET_ACTIVE_WINDOW",  False);
     Atom net_close        = XInternAtom(wm->dpy, "_NET_CLOSE_WINDOW",   False);
     Atom wm_change_state  = XInternAtom(wm->dpy, "WM_CHANGE_STATE",     False);
+    Atom net_wm_desktop   = XInternAtom(wm->dpy, "_NET_WM_DESKTOP",     False);
 
     /* _NET_CURRENT_DESKTOP → switch virtual desktop */
     if (e->message_type == wm->net_current_desktop && e->window == wm->root) {
@@ -143,6 +145,13 @@ void on_client_message(WM *wm, XClientMessageEvent *e) {
         return;
     }
 
+    /* _NET_WM_DESKTOP → move window to desktop */
+    if (e->message_type == net_wm_desktop) {
+        Client *c = client_find_by_win(wm, e->window);
+        if (c) client_move_to_desktop(wm, c, (int)e->data.l[0]);
+        return;
+    }
+
     if (e->message_type == net_active) {
         Client *c = client_find_by_win(wm, e->window);
         if (c) client_restore(wm, c);
@@ -208,6 +217,14 @@ void on_property_notify(WM *wm, XPropertyEvent *e) {
 }
 
 void on_button_press(WM *wm, XButtonEvent *e) {
+    /* Exposé — click on any frame to select and exit */
+    if (wm->expose_active) {
+        Client *c = client_find_by_frame(wm, e->window);
+        if (c) expose_hide(wm, c->frame);
+        else   expose_hide(wm, None);
+        return;
+    }
+
     /* menu window */
     if (wm->menu_visible && e->window == wm->menu_win) {
         if (e->button == Button1) menu_click(wm, e->x, e->y);
@@ -401,9 +418,45 @@ void on_key_press(WM *wm, XKeyEvent *e) {
     if ((e->state & Mod4Mask) && sym == XK_Down && wm->focused)
         client_unmaximize(wm, wm->focused);
 
-    /* Escape — hide menu */
-    if (sym == XK_Escape && wm->menu_visible)
-        menu_hide(wm);
+    /* Super+Space — Exposé window overview */
+    if ((e->state & Mod4Mask) && sym == XK_space) {
+        if (wm->expose_active) expose_hide(wm, None);
+        else                   expose_show(wm);
+        return;
+    }
+
+    /* Super+1-4 — switch to desktop N */
+    if ((e->state & Mod4Mask) && !(e->state & ShiftMask)) {
+        int desk = -1;
+        if (sym == XK_1) desk = 0;
+        else if (sym == XK_2) desk = 1;
+        else if (sym == XK_3) desk = 2;
+        else if (sym == XK_4) desk = 3;
+        if (desk >= 0) {
+            if (wm->expose_active) expose_hide(wm, None);
+            wm_switch_desktop(wm, desk);
+            return;
+        }
+    }
+
+    /* Super+Shift+1-4 — move focused window to desktop N */
+    if ((e->state & Mod4Mask) && (e->state & ShiftMask) && wm->focused) {
+        int desk = -1;
+        if (sym == XK_1) desk = 0;
+        else if (sym == XK_2) desk = 1;
+        else if (sym == XK_3) desk = 2;
+        else if (sym == XK_4) desk = 3;
+        if (desk >= 0) {
+            client_move_to_desktop(wm, wm->focused, desk);
+            return;
+        }
+    }
+
+    /* Escape — hide menu or exit Exposé */
+    if (sym == XK_Escape) {
+        if (wm->expose_active) expose_hide(wm, None);
+        else if (wm->menu_visible) menu_hide(wm);
+    }
 }
 
 void on_key_release(WM *wm, XKeyEvent *e) {