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/components/AppFooter.vue

@@ -0,0 +1,13 @@
+<template>
+  <div>
+    
+  </div>
+</template>
+
+<script lang="ts" setup>
+
+</script>
+
+<style>
+
+</style>

app/components/AppHeader.vue

@@ -0,0 +1,119 @@
+<script setup lang="ts">
+import { AGENTS } from '~~/types'
+
+const colorMode = useColorMode()
+const isDark = ref(colorMode.value === 'dark')
+watch(isDark, () => {
+  colorMode.preference = colorMode.value === 'dark' ? 'light' : 'dark'
+})
+
+const agentRoutes = AGENTS.map(item => ({
+  slug: item.slug,
+  name: item.name,
+  icon: item.icon,
+  to: `/${item.slug}`
+}))
+
+async function toggleTheme() {
+  document.body.style.animation = 'switch-on .5s'
+  await new Promise(resolve => setTimeout(resolve, 500))
+
+  isDark.value = !isDark.value
+  document.body.style.animation = 'switch-off .5s'
+
+  await new Promise(resolve => setTimeout(resolve, 500))
+  document.body.style.animation = ''
+}
+
+const router = useRouter()
+defineShortcuts({
+  t: () => toggleTheme(),
+  backspace: () => router.back()
+})
+</script>
+
+<template>
+  <header class="flex md:items-center justify-between my-8 gap-2">
+    <NuxtLink
+      class="text-xl sm:text-3xl text-nowrap gap-2 font-bold duration-300 text-neutral-600 hover:text-black dark:text-neutral-400 dark:hover:text-white"
+      to="/"
+    >
+      Art'Agents
+    </NuxtLink>
+    <nav class="flex gap-2 items-center justify-end flex-wrap">
+      <UTooltip
+        v-for="agent in agentRoutes"
+        :key="agent.slug"
+        :text="agent.name"
+        :delay-duration="4"
+      >
+        <UButton
+          :icon="agent.icon"
+          :href="agent.to"
+          :aria-label="agent.name"
+          color="neutral"
+          size="sm"
+          variant="ghost"
+        />
+      </UTooltip>
+      <UTooltip
+        :delay-duration="4"
+        text="Status page"
+      >
+        <UButton
+          icon="i-ph-warning-duotone"
+          target="_blank"
+          href="https://status.arthurdanjou.fr"
+          color="neutral"
+          size="sm"
+          variant="ghost"
+        />
+      </UTooltip>
+      <USeparator
+        orientation="vertical"
+        class="h-6"
+      />
+      <ClientOnly>
+        <UTooltip
+          :kbds="['T']"
+          text="Change theme"
+          class="cursor-pointer"
+          :delay-duration="4"
+        >
+          <UButton
+            :icon="isDark ? 'i-ph-moon-duotone' : 'i-ph-sun-duotone'"
+            color="neutral"
+            aria-label="switch theme"
+            size="sm"
+            variant="ghost"
+            @click="toggleTheme()"
+          />
+        </UTooltip>
+      </ClientOnly>
+    </nav>
+  </header>
+</template>
+
+<style>
+@keyframes switch-on {
+  0% {
+    filter: blur(0);
+    transform: scale(1);
+  }
+  100% {
+    transform: scale(0.98);
+    filter: blur(3px);
+  }
+}
+
+@keyframes switch-off {
+  0% {
+    transform: scale(0.98);
+    filter: blur(3px);
+  }
+  100% {
+    filter: blur(0);
+    transform: scale(1);
+  }
+}
+</style>