Remove allowDuringStreaming flag - commands always run immediately

Hook commands now always execute immediately, even during streaming.
If a command needs to interact with the LLM, it uses pi.sendMessage()
which handles queueing automatically.

This simplifies the API and eliminates the issue of queued slash
commands being sent to the LLM instead of executing.

packages/coding-agent/examples/hooks/snake.ts

@@ -309,7 +309,7 @@ const SNAKE_SAVE_TYPE = "snake-save";
 export default function (pi: HookAPI) {
 	pi.registerCommand("snake", {
 		description: "Play Snake!",
-		allowDuringStreaming: true, // Run even during streaming, not queued
+
 		handler: async (ctx) => {
 			if (!ctx.hasUI) {
 				ctx.ui.notify("Snake requires interactive mode", "error");