Improve error handling, Docker healthchecks, and offline sync functionality

- Move Docker healthcheck from Dockerfile to docker-compose files for better
  environment-specific configuration
- Add silent flag to healthcheck curl commands to reduce log noise
- Add error handling for missing link_templates table in client view
- Improve offline sync date formatting with ISO 8601 conversion helper
- Enhance error handlers and profile edit template

This improves robustness when migrations haven't been run and provides
better date handling in offline sync scenarios.

docker-compose.remote-dev.yml

@@ -40,7 +40,7 @@ services:
         condition: service_healthy
     restart: unless-stopped
     healthcheck:
-      test: ["CMD", "curl", "-f", "http://localhost:8080/_health"]
+      test: ["CMD", "curl", "-f", "-s", "-o", "/dev/null", "http://localhost:8080/_health"]
       interval: 30s
       timeout: 10s
       retries: 3