fix(staging): correct chat-backend health check path to /api/v1/health

The chat-backend NestJS health endpoint is at /api/v1/health, not /api/health.
This was causing the container to be marked as unhealthy, preventing chat-web
from starting due to its depends_on condition.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

docker-compose.staging.yml

@@ -112,7 +112,7 @@ services:
     ports:
       - "3002:3002"
     healthcheck:
-      test: ["CMD", "wget", "--no-verbose", "--tries=1", "--spider", "http://localhost:3002/api/health"]
+      test: ["CMD", "wget", "--no-verbose", "--tries=1", "--spider", "http://localhost:3002/api/v1/health"]
       interval: 30s
       timeout: 10s
       retries: 3