feat(noitu): add the noitu HTML5 Telegram game

Serve the BotFather game noitu from the bot's HTTP server under
/games/noitu when GAME_BASE_URL is set. /noitu sends the game, Play
answers with a signed, expiring link, and the server validates every
word against the embedded noitu dictionary (CC BY-SA 4.0), runs the
bot opponent and turn timer, and reports the score with setGameScore.

Modules can now register game-short-name callbacks and HTTP routes.

cmd/server/command_menu_test.go

@@ -73,6 +73,7 @@ func TestCommandDiscovery_AllPublicCommandsHaveSafeMetadata(t *testing.T) {
 		"loldle":               "[champion]",
 		"monkeyd_crawl":        "<url> [font_size]",
 		"monkeyd_tags":         "<url>",
+		"noitu":                "",
 		"random":               "<option,...>",
 		"addsticker":           "[emoji...]",
 		"alias":                "<name>",