feat(event): introduce .bell system event

src/container.zig

@@ -915,6 +915,11 @@ pub fn Container(Model: type, Event: type) type {
                     relative_mouse.y -= this.origin.y;
                     try this.element.handle(model, .{ .mouse = relative_mouse });
                 },
+                .bell => {
+                    // ring the terminal bell and do not propagate the event any further
+                    _ = try terminal.ringBell();
+                    return;
+                },
                 else => try this.element.handle(model, event),
             }
             for (this.elements.items) |*element| try element.handle(model, event);
@@ -961,6 +966,7 @@ const assert = std.debug.assert;
 const Allocator = std.mem.Allocator;
 const build_options = @import("build_options");
 const input = @import("input.zig");
+const terminal = @import("terminal.zig");
 const isTaggedUnion = @import("event.zig").isTaggedUnion;
 const Cell = @import("cell.zig");
 const Color = @import("color.zig").Color;

src/event.zig

@@ -13,6 +13,9 @@ pub const SystemEvent = union(enum) {
     /// Usually no `Container` nor `Element` should act on that event, as it
     /// only serves for event based loops to force a re-draw with a new `Event`.
     resize,
+    /// Ring the terminal bell to notify the user. This `Event` is handled by
+    /// every `Container` and will not be passed through the container tree.
+    bell,
     /// Error event to notify other containers about a recoverable error
     err: struct {
         /// actual error

src/terminal.zig

@@ -54,6 +54,10 @@ pub fn disableMouseSupport() !void {
     _ = try posix.write(posix.STDIN_FILENO, ctlseqs.mouse_reset);
 }
 
+pub fn ringBell() !void {
+    _ = try posix.write(posix.STDIN_FILENO, &.{7});
+}
+
 pub fn read(buf: []u8) !usize {
     return try posix.read(posix.STDIN_FILENO, buf);
 }