feat(confidence-engine): establish authenticated product boundary

app/api/cases/update/route.js

@@ -2,6 +2,7 @@ import { updateCase, reconsiderCompletedEpisode } from "@/lib/graph/orchestrator
 import { applyValidatedProposal } from "@/lib/graph/apply-proposal.js";
 import { prepareCompletedEpisode } from "@/lib/graph/episode-preparation.js";
 import { updateCaseEpisodeRequestSchema } from "@/lib/graph/schema.js";
+import { withAuthenticatedApi } from "@/lib/supabase/api-auth.js";
 
 function mapFailureStatus(result) {
   switch (result?.stage) {
@@ -35,7 +36,7 @@ function buildFailureResponse(result) {
   };
 }
 
-export async function POST(request) {
+async function post(request) {
   try {
     const body = await request.json();
     const isEpisodeMode = body?.episodeMode === true;
@@ -89,6 +90,8 @@ export async function POST(request) {
   }
 }
 
+export const POST = withAuthenticatedApi(post);
+
 /** Server-side completed-episode reconsideration flow. */
 async function handleEpisodeMode(situationGraph, body) {
   const prepared = prepareCompletedEpisode({