Add clear command

src/builtin/builtin.zig

@@ -12,6 +12,7 @@ const commands = std.StaticStringMap(CommandFn).initComptime(.{
     .{ "command", @import("cmds/command.zig").execute },
     .{ "run", @import("cmds/run.zig").execute },
     .{ "echo", @import("cmds/echo.zig").execute },
+    .{ "clear", @import("cmds/clear.zig").execute },
     .{ "exit", @import("cmds/exit.zig").execute },
 });
 

src/builtin/cmds/clear.zig

@@ -0,0 +1,10 @@
+const std = @import("std");
+
+const types = @import("../types.zig");
+
+pub fn execute(ctx: types.CommandContext) !void {
+    try ctx.stdout.writeStreamingAll(
+        ctx.io,
+        "\x1b[2J\x1b[H",
+    );
+}