fix: vitest rejects pattern + runtime config

- Fix 4 liquid-render tests: expect(async()=>{}).rejects → expect(promise).rejects
- proman.yaml: runtime bun → node (matches actual stack)
- package.json: test script uses vitest directly (avoid proman recursion)
- Add changeset for 0.2.1 patch (clean dist)

package.json

@@ -11,7 +11,7 @@
   },
   "scripts": {
     "build": "proman build",
-    "test": "proman test",
+    "test": "vitest run",
     "check": "proman check",
     "format": "proman format"
   },