fix(pe-guide): correct route imports (prod 500 regression)

The route destructured PROMPTS/INJECTION_GUARD/wrapUserText from
../utils/prompts, but PROMPTS is the module's default export and the
other two live in ../utils/promptSafe. All three resolved to undefined,
so every /api/generate-pe-narrative request crashed with
"Cannot read properties of undefined (reading 'peGuideNarrative')"
and the client surfaced "Request failed" for PE Guide narrative and
summary generation. Split the require into the two-line form that
every other AI route already uses.

src/routes/peGuide.js

@@ -10,7 +10,8 @@
 var express = require('express');
 var router = express.Router();
 var { callAI } = require('../utils/ai');
-var { PROMPTS, INJECTION_GUARD, wrapUserText } = require('../utils/prompts');
+var PROMPTS = require('../utils/prompts');
+var { wrapUserText, INJECTION_GUARD } = require('../utils/promptSafe');
 var { authMiddleware } = require('../middleware/auth');
 var logger = require('../utils/logger');