fix(a11y): label per-reminder toggles and wire disclosure controls

The diabetes PATCH parsed its body without a size cap; bound it through
safeJson like the sibling routes. Label each reminder's enable/disable switch
by its own name span so screen readers hear the reminder rather than one
generic label repeated per row. Point the chronotype and illness disclosure
triggers at the regions they reveal via aria-controls.

src/app/api/auth/me/diabetes/route.ts

@@ -19,12 +19,13 @@
  */
 import { z } from "zod";
 
-import { apiHandler, requireAuth, HttpError } from "@/lib/api-handler";
+import { apiHandler, requireAuth } from "@/lib/api-handler";
 import {
   apiError,
   apiSuccess,
   getClientIp,
   returnAllZodIssues,
+  safeJson,
 } from "@/lib/api-response";
 import { annotate } from "@/lib/logging/context";
 import { auditLog } from "@/lib/auth/audit";
@@ -74,12 +75,12 @@ export const PATCH = apiHandler(async (req: Request) => {
     return response;
   }
 
-  let body: unknown;
-  try {
-    body = await req.json();
-  } catch {
-    throw new HttpError(422, "diabetes.body.invalid_json");
-  }
+  // The body is a single boolean — bound the parse so a malformed or
+  // oversized payload is rejected before it is materialised.
+  const { data: body, error: jsonError } = await safeJson(req, {
+    maxBytes: 1024,
+  });
+  if (jsonError) return jsonError;
 
   const parsed = patchBodySchema.safeParse(body);
   if (!parsed.success) {