fix: macOS Korean IME trigger key handling

Port of rust-windowing#4478 to v0.30.13.

Bug 1 - Space double input: Clear marked_text immediately after commit
to prevent subsequent insertText calls from being treated as IME commits.

Bug 2 - Trigger key drop (comma, period, etc.): Remove the early return
guard in doCommandBySelector when ImeState::Committed, which was
swallowing ASCII key commands after IME commit.

When upstream PR rust-windowing#4478 is merged and released,
this fork should be replaced with the official winit release.

Reference: rust-windowing#4478

Author: zilhak

src/platform_impl/macos/view.rs

@@ -409,9 +409,20 @@ declare_class!(
 
             // Commit only if we have marked text.
             if unsafe { self.hasMarkedText() } && self.is_ime_enabled() && !is_control {
+                // Clear marked text as required by the NSTextInputClient protocol.
+                // This prevents subsequent insertText calls (e.g., for a trailing
+                // space) from incorrectly seeing stale marked text.
+                *self.ivars().marked_text.borrow_mut() = NSMutableAttributedString::new();
+
                 self.queue_event(WindowEvent::Ime(Ime::Preedit(String::new(), None)));
                 self.queue_event(WindowEvent::Ime(Ime::Commit(string)));
                 self.ivars().ime_state.set(ImeState::Committed);
+            } else if self.ivars().ime_state.get() == ImeState::Committed && !is_control {
+                // After committing composed text (e.g., Korean "한"), the IME may
+                // send a second insertText for the triggering character (e.g.,
+                // space). Forward it to the app as a regular key event instead of
+                // committing it again through IME, which would cause double input.
+                self.ivars().forward_key_to_app.set(true);
             }
         }
 
@@ -420,12 +431,6 @@ declare_class!(
         #[method(doCommandBySelector:)]
         fn do_command_by_selector(&self, _command: Sel) {
             trace_scope!("doCommandBySelector:");
-            // We shouldn't forward any character from just committed text, since we'll end up sending
-            // it twice with some IMEs like Korean one. We'll also always send `Enter` in that case,
-            // which is not desired given it was used to confirm IME input.
-            if self.ivars().ime_state.get() == ImeState::Committed {
-                return;
-            }
 
             self.ivars().forward_key_to_app.set(true);