feat: validate and describe reserved command arguments

app/game-api/src/paths.ts

@@ -0,0 +1,18 @@
+import fs from 'node:fs';
+import path from 'node:path';
+
+const hasWorkspaceMarker = (dir: string): boolean => fs.existsSync(path.join(dir, 'pnpm-workspace.yaml'));
+
+export const resolveWorkspaceRoot = (
+    startDir: string = process.env.GAME_WORKSPACE_ROOT ?? process.env.GATEWAY_WORKSPACE_ROOT ?? process.cwd(),
+    maxDepth = 6
+): string => {
+    let current = path.resolve(startDir);
+    for (let depth = 0; depth <= maxDepth; depth += 1) {
+        if (hasWorkspaceMarker(current)) return current;
+        const parent = path.dirname(current);
+        if (parent === current) break;
+        current = parent;
+    }
+    return path.resolve(startDir);
+};