Reconnect to a restarted Wayland compositor

Windows now outlive the compositor. On connection loss YASL sends
DISPLAY_LOST instead of closing every window, retries the connection on
a loop timer, rebuilds each toplevel with its title, size, state and GL
context, and sends DISPLAY_RESTORED. CPU windows keep their pixels;
GPU renderers drop Vulkan surfaces and GL objects on loss and rebuild
them on restore.

- Free the dead connection's objects on the next wait, after the
  application has released GPU objects built on them.
- Report a lost connection as an event rather than a failed wait.
- Refuse window and Vulkan surface creation while offline with the new
  YASL_ERROR_DISCONNECTED.
- Close popups, cancel drags and fail pending clipboard requests on loss.
- Print only protocol errors, not ordinary disconnects.
- Examples survive a restart; game.c rebinds its GL context.
- Add an end-to-end test that kills Weston under CPU, GL and Vulkan
  windows and requires them to recover.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/src/platform/wayland/buffer.c b/src/platform/wayland/buffer.c
index bbc055d..029b684 100644
--- a/src/platform/wayland/buffer.c
+++ b/src/platform/wayland/buffer.c
@@ -211,6 +211,7 @@ static const struct wp_fractional_scale_v1_listener frac_scale_listener = {
 
 void surface_follow_outputs(struct wayland_surface *w)
 {
+    if (!w->surface) return; /* Not rebuilt yet after a reconnect. */
     uint32_t refresh = 0;
     int32_t max_scale = 0;
     bool need_scale = !w->frac_scale &&
@@ -563,11 +564,12 @@ int surface_init_scaling(struct wayland_surface *w)
 
 void wayland_surface_set_title(struct wayland_surface *w, const char *title)
 {
-    if (!w || !w->toplevel || !title) return;
+    if (!w || !title) return;
     char *copy = yasl_private_utf8_sanitize_dup(title);
     if (!copy) return;
-    xdg_toplevel_set_title(w->toplevel, copy);
-    free(copy);
+    free(w->title);
+    w->title = copy;
+    if (w->toplevel) xdg_toplevel_set_title(w->toplevel, copy);
 }
 
 struct yasl_private_timing wayland_surface_timing(const struct wayland_surface *w)