feat: refine portfolio content, contact, and supporting media

tests/fixtures/portfolio-content.valid.json

@@ -111,7 +111,7 @@
   }],
   "contact": {
     "introduction": "Open to System Administrator and Full-Stack Developer opportunities.",
-    "email": "hello@example.test",
+    "email": { "localPart": "hello", "domain": "example.test" },
     "social": [{ "service": "GitHub", "url": "https://github.com/example" }],
     "cvMessage": "For a current CV or role-specific information, contact me directly."
   },