core: optimize struct layouts, eliminate branches, and fix event loop dispatch

- Fix Wayland event loop lockout by properly decoupling read arming and adding poll-backed dispatching
- Support standalone display lifecycle without requiring caller to manage a loop
- Eliminate alignment holes across yasl_surface, yasl_display, seat, touch_point, and conn_drag using pahole
- Replace branching state/button decoders with compile-time locked LUTs and branchless bitwise operations
- Accelerate UTF-8 validation with 64-bit word scanning for ASCII runs

1 files changed, 5 insertions, 7 deletions

diff --git a/src/wayland/keyboard.c b/src/wayland/keyboard.c
index 7283d58..6045962 100644
--- a/src/wayland/keyboard.c
+++ b/src/wayland/keyboard.c
@@ -346,13 +346,11 @@ static bool mod_index_active(const struct seat *s, xkb_mod_index_t mod)
 
 int seat_modifiers(const struct seat *s)
 {
-    if (!s || !s->xkb_state) return 0;
-    int mods = 0;
-    if (mod_index_active(s, s->mod_shift)) mods |= YASL_MOD_SHIFT;
-    if (mod_index_active(s, s->mod_alt))   mods |= YASL_MOD_ALT;
-    if (mod_index_active(s, s->mod_ctrl))  mods |= YASL_MOD_CTRL;
-    if (mod_index_active(s, s->mod_super)) mods |= YASL_MOD_SUPER;
-    return mods;
+    if (unlikely(!s || !s->xkb_state)) return 0;
+    return (mod_index_active(s, s->mod_shift) * YASL_MOD_SHIFT) |
+           (mod_index_active(s, s->mod_alt)   * YASL_MOD_ALT)   |
+           (mod_index_active(s, s->mod_ctrl)  * YASL_MOD_CTRL)  |
+           (mod_index_active(s, s->mod_super) * YASL_MOD_SUPER);
 }
 
 int yasl_display_modifiers(const struct yasl_display *c)