feat: add FilesBlock interface and component integration

- Introduced FilesBlockItem and FilesBlockData interfaces to support file handling in the CMS.
- Integrated FilesBlock component into ContentRows.svelte for rendering file blocks.
- Updated block type handling to include support for files, enhancing content versatility.

src/routes/cms-files/+server.ts

@@ -0,0 +1,103 @@
+import type { RequestHandler } from './$types';
+import { env } from '$env/dynamic/public';
+import {
+  buildFileCacheKey,
+  cacheFile,
+  contentTypeFromExt,
+  extFromSrc,
+  getCachedFile,
+} from '$lib/file-cache.server';
+
+const IMMUTABLE_HEADERS = {
+  'cache-control': 'public, max-age=31536000, immutable',
+} as const;
+
+function getCmsBaseUrl(): string {
+  return (
+    env.PUBLIC_CMS_URL ||
+    import.meta.env.PUBLIC_CMS_URL ||
+    'http://localhost:3000'
+  ).replace(/\/$/, '');
+}
+
+function resolveSourceUrl(src: string): string {
+  if (src.startsWith('http://') || src.startsWith('https://')) return src;
+  if (src.startsWith('//')) return `https:${src}`;
+  if (src.startsWith('/')) return `${getCmsBaseUrl()}${src}`;
+  return `${getCmsBaseUrl()}/api/assets/${encodeURIComponent(src)}`;
+}
+
+function buildResponseHeaders(
+  contentType: string,
+  download: string | null,
+  filename?: string,
+): HeadersInit {
+  const headers: Record<string, string> = {
+    'content-type': contentType,
+    ...IMMUTABLE_HEADERS,
+  };
+  if (download === '1' || download === 'true') {
+    const safe = (filename ?? 'download').replace(/"/g, '');
+    headers['content-disposition'] = `attachment; filename="${safe}"`;
+  } else if (filename) {
+    const safe = filename.replace(/"/g, '');
+    headers['content-disposition'] = `inline; filename="${safe}"`;
+  }
+  return headers;
+}
+
+export const GET: RequestHandler = async ({ url }) => {
+  const src = url.searchParams.get('src');
+  if (!src) {
+    return new Response('Missing "src" parameter', { status: 400 });
+  }
+  const download = url.searchParams.get('dl');
+  const filenameParam = url.searchParams.get('name') ?? undefined;
+  const inferredName = (() => {
+    try {
+      const path = src.split('?')[0].split('#')[0];
+      const last = path.split('/').pop();
+      return last ? decodeURIComponent(last) : undefined;
+    } catch {
+      return undefined;
+    }
+  })();
+  const filename = filenameParam ?? inferredName;
+
+  const key = buildFileCacheKey(src);
+
+  const cached = await getCachedFile(key);
+  if (cached) {
+    return new Response(new Uint8Array(cached.buffer), {
+      headers: buildResponseHeaders(cached.contentType, download, filename),
+    });
+  }
+
+  const sourceUrl = resolveSourceUrl(src);
+  let res: Response;
+  try {
+    res = await fetch(sourceUrl);
+  } catch (err) {
+    console.error('[cms-files] CMS fetch failed:', err);
+    return new Response('CMS not reachable', { status: 502 });
+  }
+
+  if (!res.ok) {
+    return new Response('File fetch failed', { status: res.status });
+  }
+
+  const buffer = await res.arrayBuffer();
+  const upstreamCt = res.headers.get('content-type') ?? '';
+  const ext = extFromSrc(src);
+  const contentType = upstreamCt && !upstreamCt.startsWith('application/octet-stream')
+    ? upstreamCt
+    : ext
+      ? contentTypeFromExt(ext)
+      : upstreamCt || 'application/octet-stream';
+
+  const result = await cacheFile(key, buffer, contentType, src);
+
+  return new Response(new Uint8Array(result.buffer), {
+    headers: buildResponseHeaders(result.contentType, download, filename),
+  });
+};