fix: update deploy.sh comments to reference correct ports

## Summary
Fixed deploy.sh comments to reference correct port numbers.

## Problem
The deploy.sh header comments referenced ports 4200/4201, but the actual
docker-compose.yml maps ports 8765/8766. This caused confusion when
deploying.

## Solution
Updated comments to reflect actual port mappings:
- nexus-main: port 8765 (was 4200)
- nexus-staging: port 8766 (was 4201)

## Changes
- Updated deploy.sh header comments with correct port numbers
- No functional changes to deployment logic

Issue: #1413

deploy.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 # deploy.sh — spin up (or update) the Nexus staging environment
-# Usage: ./deploy.sh          — rebuild and restart nexus-main (port 4200)
-#        ./deploy.sh staging  — rebuild and restart nexus-staging (port 4201)
+# Usage: ./deploy.sh          — rebuild and restart nexus-main (port 8765)
+#        ./deploy.sh staging  — rebuild and restart nexus-staging (port 8766)
 set -euo pipefail
 
 SERVICE="${1:-nexus-main}"