Switch exec to fire-and-forget spawn, drop awaits

spawnSync was blocking the event loop until the subprocess exited, so
opening a browser would freeze the server until it closed. Replace with
spawn + unref (detached, stdio ignored) and remove the now-pointless
awaits and async keywords from action handlers.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/helpers.mjs

@@ -1,4 +1,4 @@
-import { spawnSync } from "child_process";
+import { spawn } from "child_process";
 import path from "path";
 
 const CONTAINER_PATH = "/home/devilholk/Projekt/claude-docker/";
@@ -24,14 +24,7 @@ export function resolve_path(user_path) {
 	throw new Error(`Path is outside all known volumes: ${user_path}`);
 }
 
-// Execute a binary with an argument list — no shell interpolation.
+// Launch a binary with an argument list — no shell interpolation, fire and forget.
 export function exec(bin, args = []) {
-	return new Promise((resolve, reject) => {
-		const result = spawnSync(bin, args, { stdio: "inherit" });
-		if (result.error) {
-			reject(result.error);
-		} else {
-			resolve(result.status);
-		}
-	});
+	spawn(bin, args, { stdio: 'ignore', detached: true }).unref();
 }