feat: initialise Vue 3 SPA template

- Add Tailwind CSS v4 with light/dark theme support
- Add layout system (default, sidebar, blank)
- Add mock authentication with Pinia store and route guards
- Add error pages (404, 500) and example views
- Add Vitest with 10 example tests across stores
- Configure Prettier formatting and ESLint linting

eslint.config.ts

@@ -0,0 +1,26 @@
+import { globalIgnores } from 'eslint/config'
+import { defineConfigWithVueTs, vueTsConfigs } from '@vue/eslint-config-typescript'
+import pluginVue from 'eslint-plugin-vue'
+import pluginOxlint from 'eslint-plugin-oxlint'
+import skipFormatting from 'eslint-config-prettier/flat'
+
+// To allow more languages other than `ts` in `.vue` files, uncomment the following lines:
+// import { configureVueProject } from '@vue/eslint-config-typescript'
+// configureVueProject({ scriptLangs: ['ts', 'tsx'] })
+// More info at https://github.com/vuejs/eslint-config-typescript/#advanced-setup
+
+export default defineConfigWithVueTs(
+  {
+    name: 'app/files-to-lint',
+    files: ['**/*.{vue,ts,mts,tsx}'],
+  },
+
+  globalIgnores(['**/dist/**', '**/dist-ssr/**', '**/coverage/**']),
+
+  ...pluginVue.configs['flat/essential'],
+  vueTsConfigs.recommended,
+
+  ...pluginOxlint.buildFromOxlintConfigFile('.oxlintrc.json'),
+
+  skipFormatting,
+)