feat(swagger): support dynamic host via EZ_SWAGGER_HOST env var

- Add ServerConfig.SwaggerHost field
- Set docs.SwaggerInfo.Host dynamically at startup
- Update docker-compose, k8s manifests, and .env.example

test/k8s/ez-api.yaml

@@ -153,6 +153,12 @@ spec:
                 configMapKeyRef:
                   name: ez-api-config
                   key: EZ_LOG_PARTITIONING
+            # Swagger Host
+            - name: EZ_SWAGGER_HOST
+              valueFrom:
+                configMapKeyRef:
+                  name: ez-api-config
+                  key: EZ_SWAGGER_HOST
           resources:
             requests:
               memory: "128Mi"