Fix Docker Compose default profile and error documentation

- Add 'default' profile to all services so 'docker compose up --build -d' works without --profile flag
- Update BackendStartupError.tsx to include '--profile full' in Docker command examples
- Update docker-compose.yml comments to document the new default behavior

This allows users to run either:
- docker compose up --build -d (uses default profile, starts all services)
- docker compose --profile full up --build -d (explicit profile, same result)
- docker compose --profile backend up --build -d (backend services only)

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

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

archon-ui-main/src/components/BackendStartupError.tsx

@@ -49,7 +49,7 @@ export const BackendStartupError: React.FC = () => {
                   After fixing the issue in your .env file, recreate the Docker containers:
                 </p>
                 <code className="block mt-2 p-2 bg-black/70 rounded text-red-100 font-mono text-sm">
-                  docker compose down && docker compose up -d
+                  docker compose down && docker compose --profile full up -d
                 </code>
                 <p className="text-red-300 text-xs mt-2">
                   Note: Use 'down' and 'up', not 'restart' - containers need to be recreated to load new environment variables