fix(12): satisfy CI fast-checks — lint unused vars, typed contract-test body, prettier

- Remove unused 'res'/'container' assignments (no-unused-vars)
- setupClient.contract.test.ts: typed parseSentBody helper + non-async json mock
  (no-unsafe-*/require-await)
- Prettier format 7 setup files

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/pwa/src/api/client.ts

@@ -636,7 +636,9 @@ export async function validateSetupDb(): Promise<void> {
   if (res.status === 423) throw new SetupAlreadyLockedError();
 
   if (!res.ok) {
-    throw new Error('Cannot reach the database. Check DB_HOST, DB_PORT, DB_USER, DB_PASSWORD in your Docker environment and try again.');
+    throw new Error(
+      'Cannot reach the database. Check DB_HOST, DB_PORT, DB_USER, DB_PASSWORD in your Docker environment and try again.',
+    );
   }
 }
 
@@ -650,7 +652,9 @@ export async function validateSetupOidc(): Promise<void> {
   if (res.status === 423) throw new SetupAlreadyLockedError();
 
   if (!res.ok) {
-    throw new Error('OIDC discovery failed. Check the issuer URL and that Authelia is reachable from the server.');
+    throw new Error(
+      'OIDC discovery failed. Check the issuer URL and that Authelia is reachable from the server.',
+    );
   }
 }
 
@@ -663,7 +667,9 @@ export async function validateSetupVapid(): Promise<void> {
   if (res.status === 423) throw new SetupAlreadyLockedError();
 
   if (!res.ok) {
-    throw new Error('VAPID validation failed. Check that your VAPID keys were generated with `npm run generate-secrets`.');
+    throw new Error(
+      'VAPID validation failed. Check that your VAPID keys were generated with `npm run generate-secrets`.',
+    );
   }
 }
 
@@ -686,7 +692,9 @@ export async function postSetupCredential(payload: SetupCredentialPayload): Prom
   if (res.status === 423) throw new SetupAlreadyLockedError();
 
   if (!res.ok) {
-    throw new Error("Invalid password — CalDAV validation failed. Check the scope is 'Calendars & Contacts (CalDAV)' and try again.");
+    throw new Error(
+      "Invalid password — CalDAV validation failed. Check the scope is 'Calendars & Contacts (CalDAV)' and try again.",
+    );
   }
 }