scaffold blog_portal vue 3 + pinia + cypress frontend

Mirrors youngstartup/frontend/startups_portal scaffolding:
Vite, Vue 3 (composition API + script setup), TypeScript strict,
Pinia, Vue Router 5, oxlint + eslint + oxfmt, and Cypress with
db:reset / db:seed tasks. Views and the auth store are stubs
filled in by the next branches; routes and the header chrome
are wired so the build passes.

frontend/blog_portal/.oxlintrc.json

@@ -0,0 +1,10 @@
+{
+  "$schema": "./node_modules/oxlint/configuration_schema.json",
+  "plugins": ["eslint", "typescript", "unicorn", "oxc", "vue"],
+  "env": {
+    "browser": true
+  },
+  "categories": {
+    "correctness": "error"
+  }
+}