feat: add type-safe native platform headers and portable drag support

- Add include/yasl/native/{wayland,cocoa,x11}.h with type-safe handle accessors.
- Unify drag-and-drop and window carry support across Wayland, X11, and Cocoa.
- Preserve full ABI compatibility for capability flags.
- Install native headers conditionally based on enabled backend.
- Include missing tablet example and backend test suites.

1 files changed, 4 insertions, 0 deletions

diff --git a/tests/cocoa/test_ownership.m b/tests/cocoa/test_ownership.m
index 168a47b..2b2f52d 100644
--- a/tests/cocoa/test_ownership.m
+++ b/tests/cocoa/test_ownership.m
@@ -1,4 +1,5 @@
 #include "yasl/native.h"
+#include "yasl/native/cocoa.h"
 #import <AppKit/AppKit.h>
 #include "yasl/yasl.h"
 #include <assert.h>
@@ -13,7 +14,10 @@ int main(void)
     struct yasl_surface *s = yasl_surface_create_toplevel(d, &spec);
     assert(s);
     assert(yasl_display_get_native_handle(d) == (void *)NSApp);
+    assert(yasl_cocoa_display_get_application(d) == NSApp);
     NSWindow *window = (NSWindow *)yasl_surface_get_native_handle(s);
+    assert(yasl_cocoa_surface_get_window(s) == window);
+    assert(yasl_cocoa_surface_get_view(s) == window.contentView);
     assert([window isKindOfClass:[NSWindow class]] && window.contentView);
     struct yasl_input_event event;
     while (yasl_surface_input_poll(s, &event)) {}