fix(wizard): include request_id in apply-batch payload

Backend EA2 apply-batch requires a request_id (idempotency key). Without
it, every node/edge write after Intake was failing with HTTP 422 and the
wizard stayed stuck on the Analyze phase.

Verified via qa/audit_wizard_writes.mjs against the live URL: previously
1 successful POST (draft creation) + 6x 422, now full multi-phase
write path enabled.

src/lib/wizardApi.ts

@@ -61,16 +61,23 @@ export const wizardApi = {
   },
 
   async applyBatch(flow_key: string, ops: BatchOperation[], actor: Actor, signal?: AbortSignal) {
+    const request_id =
+      typeof crypto !== "undefined" && "randomUUID" in crypto
+        ? crypto.randomUUID()
+        : `req-${Date.now()}-${Math.random().toString(36).slice(2, 10)}`;
     const res = await fetch(`${api.config.baseUrl}/api/ea2/apply-batch`, {
       method: "POST",
       headers: {
         Authorization: `Bearer ${sessionStorage.getItem("fm.mc.token.v1")}`,
         "Content-Type": "application/json",
       },
-      body: JSON.stringify({ flow_key, ops, actor }),
+      body: JSON.stringify({ flow_key, ops, actor, request_id }),
       signal,
     });
-    if (!res.ok) throw new Error(`applyBatch failed: ${res.status}`);
+    if (!res.ok) {
+      const detail = await res.text().catch(() => "");
+      throw new Error(`applyBatch ${res.status}: ${detail.slice(0, 200)}`);
+    }
     return res.json();
   },