Keep InvoiceGuard manifest on hardened version

a2a.yaml

@@ -1,5 +1,5 @@
 name: invoice-guard-studio-v1
-version: 0.1.0
+version: 0.1.3
 entrypoint: agent:InvoiceGuardStudioV1
 expose:
   public: false

tests/test_full_stack_contract.py

@@ -29,6 +29,7 @@ def test_full_stack_product_contract():
     bridge = (ROOT / "frontend" / "src" / "a2a.js").read_text(encoding="utf-8")
 
     assert "frontend:" in manifest and "mount: /app" in manifest
+    assert f"version: {InvoiceGuardStudioV1.version}" in manifest
     assert "public: false" in manifest
     assert "resources:" in manifest and "databases:" in manifest
     assert "migrations:" in manifest and "db/migrations" in manifest