Merge branch 'backend-selection' into main

- Implement runtime backend selection (Wayland, X11, Cocoa)
- Add native X11 backend with clipboard, keyboard, mouse, and placement
- Integrate multi-backend integration tests running under Weston and Xwayland
- Retain zero-hole struct packing, branchless ALU/LUT primitives, and paced event loop

1 files changed, 5 insertions, 0 deletions

diff --git a/src/common/loop.c b/src/common/loop.c
index de29c85..ea9bee3 100644
--- a/src/common/loop.c
+++ b/src/common/loop.c
@@ -254,3 +254,8 @@ void yasl_loop_quit(struct yasl_loop *l)
 {
     if (l) l->running = false;
 }
+
+bool yasl_loop_is_running(const struct yasl_loop *l)
+{
+    return l ? l->running : false;
+}