feat: speed up admin clone import and enable Cache Components

- Clone import: defer FurnitureData.json writes and append all entries in a
  single batched write instead of one read-modify-write per item, removing
  the main serialization bottleneck for large batches.
- Clone import: raise SSE batch concurrency cap from 5 to 10 and bump the
  clone client/route default from 2 to 6.
- Add a flush hook to runSseBatch so callers can batch deferred work before
  batch_complete is emitted, and surface flush errors as an error event.
- Enable Next.js Cache Components (instant: false opt-out) and silence the
  related build warnings in next.config.ts.
- Switch isomorphic-dompurify to dompurify and refresh dependencies.

pnpm-lock.yaml

@@ -371,6 +371,9 @@ packages:
   '@emnapi/[email protected]':
     resolution: {integrity: sha512-kyOl3X0DuTiT1h2ft8r2fYO8JYtU9a9Xis/zBSiGArNaagCOWx90N1k2wxp18czFDH+OgcWGb5ZP/XMt3dcyPA==}
 
+  '@emnapi/[email protected]':
+    resolution: {integrity: sha512-Xz4Tpyki7XyrpbUK1jR1AhdAdaXyhhY4lZ3neLodmhpuWfy2PAQN5B46sAiU4liOXGLkHypn/qU+jvfWSCYYLA==}
+
   '@emnapi/[email protected]':
     resolution: {integrity: sha512-c95qOXkHdydNKhscBTebqEC1CVAZpyqOfVfBzQ1qgzyl3gfeldUjIggDbIZgDKsHLgnsM+igH7TJ/eAasaVuMA==}
 
@@ -3280,6 +3283,11 @@ snapshots:
       tslib: 2.8.1
     optional: true
 
+  '@emnapi/[email protected]':
+    dependencies:
+      tslib: 2.8.1
+    optional: true
+
   '@emnapi/[email protected]':
     dependencies:
       tslib: 2.8.1
@@ -3499,7 +3507,7 @@ snapshots:
 
   '@img/[email protected]':
     dependencies:
-      '@emnapi/runtime': 1.11.2
+      '@emnapi/runtime': 1.11.3
     optional: true
 
   '@img/[email protected]':