Simplify the public event and CPU API

Applications now need far less ceremony: hello.c is a 20-line loop that
handles REFRESH, CLOSE and QUIT and draws into the surface's own pixels.

- Fold GEOMETRY, STATE and FOCUS into one WINDOW event carrying size,
  scale and state; unchanged values send nothing.
- Guarantee REFRESH once a window has a size and after every resize,
  never at size zero.
- Merge DROP_HOVER into DROP with over/leave/data actions and give drag
  and drop actions enums.
- Keep event strings valid until the next wait and drop
  yasl_event_release; empty or failed waits report NONE.
- Replace copy-in presentation with a lent pixel buffer:
  yasl_cpu_pixels and yasl_cpu_present.
- Remove yasl_poll_event, yasl_cpu_read_pixels, unused event fields and
  comments that restated names.
- Wayland: resize floating windows in request_size instead of reporting
  it unsupported, and stop marking new GPU surfaces as Vulkan so
  yasl_vulkan_create_surface no longer fails with NATIVE_WINDOW_IN_USE.

Also includes the in-progress public API refactor that was uncommitted
in the tree (removal of the app/loop layer, new surface, GL and Vulkan
entry points).

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

1 files changed, 40 insertions, 0 deletions

diff --git a/src/common/private_native_wayland.h b/src/common/private_native_wayland.h
new file mode 100644
index 0000000..5033f7f
--- /dev/null
+++ b/src/common/private_native_wayland.h
@@ -0,0 +1,40 @@
+/**
+ * @file
+ * Typed borrowed Wayland handles; available when built with Wayland support.
+ */
+#ifndef YASL_PRIVATE_NATIVE_WAYLAND_H
+#define YASL_PRIVATE_NATIVE_WAYLAND_H
+
+#include "common/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct wl_display;
+struct wl_surface;
+
+/* Return borrowed Wayland handles (expire on display/surface destruction).
+ * Return NULL if display/surface is not a Wayland object or NULL. */
+/**
+ * Get the borrowed Wayland connection for an object of the matching backend.
+ * @param d Live display, or NULL.
+ * @return The handle, or zero/NULL for NULL or a different backend.
+ * Expires on display destruction. Available only when this backend is built.
+ * Never pass a pointer to a destroyed object.
+ */
+struct wl_display *yasl_private_wayland_display_get_wl_display(struct yasl_private_display *d);
+/**
+ * Get the borrowed Wayland surface for an object of the matching backend.
+ * @param s Live surface, or NULL.
+ * @return The handle, or zero/NULL for NULL or a different backend.
+ * Expires on surface destruction. Available only when this backend is built.
+ * Never pass a pointer to a destroyed object.
+ */
+struct wl_surface *yasl_private_wayland_surface_get_wl_surface(struct yasl_surface *s);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* YASL_PRIVATE_NATIVE_WAYLAND_H */