feat: add chat and file management APIs, implement chat loading and saving functionality

- Introduced new API endpoints for chat management including posting and retrieving chat messages.
- Implemented file upload and deletion functionalities for chat and other files.
- Added utility functions for streaming text and loading chat data.
- Created TypeScript types for models and agents used in the application.
- Configured TypeScript settings for server and project.
- Added favicon and workspace configuration for pnpm.

app/composables/chat.ts

@@ -0,0 +1,36 @@
+import type { Message } from 'ai'
+
+export async function loadChat(slug: string): Promise<Message[]> {
+  const { blobs } = await $fetch('/api/files')
+
+  if (!blobs.find(item => item.pathname === `chats/${slug}.json`)) {
+    await createChat(slug)
+  }
+
+  const data = await $fetch<string>(`/api/chats/${slug}`)
+  const dataString = JSON.stringify(data)
+
+  if (dataString === '[]') return []
+  return JSON.parse(dataString)
+}
+
+async function createChat(slug: string) {
+  await $fetch('/api/chats', {
+    method: 'POST',
+    body: {
+      file: {
+        name: `${slug}.json`,
+        content: '[]'
+      }
+    }
+  })
+}
+
+export async function deleteChat(slug: string) {
+  await $fetch('/api/files', {
+    method: 'DELETE',
+    body: {
+      pathname: `chats/${slug}.json`
+    }
+  })
+}