feat: add resources page with file management

- Add /resources page with file listing, filtering, and bulk operations
- Add useResources composable for file state management
- Add sidenav header and nav components for resources section
- Add files list API endpoint (GET /api/files)
- Track file size during upload
- Add resources link to home navigation

app/components/Sidenav/HeaderResources.vue

@@ -0,0 +1,22 @@
+<script setup lang="ts">
+const { isHovered } = useSidenavContext();
+</script>
+
+<template>
+    <header class="flex items-center rounded-lg overflow-hidden flex-1 min-w-0">
+        <div class="w-10 md:w-8 flex flex-shrink-0 items-center">
+            <NuxtLink to="/"
+                class="flex @hover:bg-[var(--color-hover)] focus-visible:bg-[var(--color-hover)] rounded-lg decoration-none transition-inherit text-[var(--text-secondary)] p-1.5">
+                <span class="i-mynaui-home text-5.5 md:text-4.5"></span>
+            </NuxtLink>
+        </div>
+
+        <div class="flex items-center gap-1 pr-1">
+            <span class="i-mynaui-chevron-right inline-block text-5 md:text-4"></span>
+            <span
+                class="md:text-sm font-medium text-ellipsis overflow-hidden text-[var(--text-secondary)] whitespace-nowrap">
+                Resources
+            </span>
+        </div>
+    </header>
+</template>