fix: add progress bar and batch download to vectorize tool

The vectorize tool had a custom processing flow that bypassed the
standard useToolProcessor hook -- no progress indication, no server-side
batch, and the Download All ZIP relied on a client-side sequential loop.

Backend: extract core logic into vectorizeBuffer(), register via
registerToolProcessFn() so the /batch endpoint works with p-queue
concurrency and SSE progress events.

Frontend: replace custom fetch loop with useToolProcessor hook and
ProgressCard, giving upload progress, per-file batch status, and
automatic Download All ZIP via the existing tool-page infrastructure.

Also set image/svg+xml MIME type on SVG blobs during batch ZIP
extraction to ensure reliable rendering in <img> tags across browsers.

apps/web/src/hooks/use-tool-processor.ts

@@ -392,7 +392,11 @@ export function useToolProcessor(toolId: string) {
         for (let i = 0; i < entries.length; i++) {
           const processedName = fileResults[String(i)];
           if (processedName && extracted[processedName]) {
-            const blob = new Blob([extracted[processedName] as BlobPart]);
+            const blobType = processedName.endsWith(".svg") ? "image/svg+xml" : undefined;
+            const blob = new Blob(
+              [extracted[processedName] as BlobPart],
+              blobType ? { type: blobType } : undefined,
+            );
             updateEntry(i, {
               processedUrl: URL.createObjectURL(blob),
               processedFilename: processedName,