feat(items): implement initial item management system

This commit introduces the foundational structure and core features for the item management application.

Key features implemented:
- **Item Listing:** A main page displaying all items in a searchable UTable.
- **Item Creation:** An "Add Item" modal with a UForm for input and validation using Zod.
- **State Management:** A `useItemsStore` composable built with `@vueuse/core`'s `useLocalStorage` to persist item data
in the browser.
- **UI Framework:** Integrated Nuxt UI for components like tables, modals, forms, and the overall layout.
- **Application Shell:** Established a default layout with a header, navigation menu, and placeholders for Export and
History pages.
- **Project Setup:** Configured pnpm workspace, Tailwind CSS, and VSCode editor settings for an improved development
experience.

.vscode/settings.json

@@ -0,0 +1,12 @@
+{
+  "files.associations": {
+    "*.css": "tailwindcss"
+  },
+  "editor.quickSuggestions": {
+    "strings": "on"
+  },
+  "tailwindCSS.classAttributes": ["class", "ui"],
+  "tailwindCSS.experimental.classRegex": [
+    ["ui:\\s*{([^)]*)\\s*}", "(?:'|\"|`)([^']*)(?:'|\"|`)"]
+  ]
+}