chore: refresh .env.deploy.example for Vercel + Upstash + add session journal

- Add Upstash REST creds, KEY_PREFIX, MONGODB_URI (one-shot migration)
- Update WORKER_URL example to Vercel format (var name retained for
  register-webhook.js compatibility; rename deferred to Phase 7)
- Track docs/journals/ entry from cook session

.env.deploy.example

@@ -1,3 +1,20 @@
+# Operator-only file: holds the credentials the deploy + migrate scripts need.
+# Copy to .env.deploy and fill in. NEVER commit .env.deploy.
+
+# Telegram (must match values set as Vercel env vars)
 TELEGRAM_BOT_TOKEN=
 TELEGRAM_WEBHOOK_SECRET=
-WORKER_URL=https://js-store-scraper-bot.<account>.workers.dev
+
+# Where Telegram should send webhook updates after Phase 6 cutover.
+# Format: https://<your-vercel-url>/api/webhook
+# Variable name kept as WORKER_URL for register-webhook.js compatibility.
+WORKER_URL=https://store-scraper-bot.vercel.app/api/webhook
+
+# Upstash Redis credentials — required by migrate-atlas-to-upstash.js
+UPSTASH_REDIS_REST_URL=
+UPSTASH_REDIS_REST_TOKEN=
+KEY_PREFIX=store-scraper-bot:
+
+# Legacy Java-bot MongoDB Atlas — required for one-shot Phase 5 migration only.
+# After successful cutover, remove this line.
+MONGODB_URI=