core: add 'command finished' notifications

Fixes #8991

Uses OSC 133 esc sequences to keep track of how long commands take to
execute. If the user chooses, commands that take longer than a user
specified limit will trigger a notification. The user can choose between
a bell notification or a desktop notification.

src/termio/stream_handler.zig

@@ -1054,6 +1054,11 @@ pub const StreamHandler = struct {
 
     pub inline fn endOfInput(self: *StreamHandler) !void {
         self.terminal.markSemanticPrompt(.command);
+        self.surfaceMessageWriter(.start_command_timer);
+    }
+
+    pub inline fn endOfCommand(self: *StreamHandler, exit_code: ?u8) !void {
+        self.surfaceMessageWriter(.{ .stop_command_timer = exit_code });
     }
 
     pub fn reportPwd(self: *StreamHandler, url: []const u8) !void {