feat: add the snippets plugin (B2)

plugins/snippets/src/backend/reorder.ts

@@ -0,0 +1,29 @@
+import type { SnippetReorderUpdate } from "./repository.js";
+
+type SnippetReorderRequestBody = {
+  snippets?: unknown;
+  updates?: unknown;
+};
+
+export function extractSnippetReorderUpdates(
+  body: unknown,
+): SnippetReorderUpdate[] | null {
+  if (!body || typeof body !== "object") {
+    return null;
+  }
+
+  const payload = body as SnippetReorderRequestBody;
+  // Keep accepting the legacy `updates` key so older clients do not break
+  // while the web and desktop helpers converge on `snippets`.
+  const snippetsUpdates = Array.isArray(payload.snippets)
+    ? payload.snippets
+    : Array.isArray(payload.updates)
+      ? payload.updates
+      : null;
+
+  if (!snippetsUpdates) {
+    return null;
+  }
+
+  return snippetsUpdates as SnippetReorderUpdate[];
+}