fix: bash operator precedence in test framework detection

[ -f a ] || [ -f b ] && X="y" evaluates as A || (B && C), so the
assignment only runs when the second test passes. Wrap the OR group
in braces: { [ -f a ] || [ -f b ]; } && X="y".

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "0.15.0.0",
+  "version": "0.15.2.0",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",