Feat: Enable MCP streamable-http model via docker compose (#9092)

### What problem does this PR solve?

Enable MCP streamable-http model via docker compose

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

docker/docker-compose.yml

-
 include:
   - ./docker-compose-base.yml
-
 # To ensure that the container processes the locally modified `service_conf.yaml.template` instead of the one included in its image, you need to mount the local `service_conf.yaml.template` to the container.
 services:
   ragflow:
     #   - --mcp-base-url=http://127.0.0.1:9380
     #   - --mcp-script-path=/ragflow/mcp/server/server.py
     #   - --mcp-mode=self-host
-    #   - --mcp-host-api-key=ragflow-xxxxxxx
+    #   - --mcp-host-api-key=ragflow-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+    # Optional transport flags for MCP (customize if needed).
+    # Host mode need to combined with --no-transport-streamable-http-enabled flag, namely, host+streamable-http is not supported yet.
+    # The following are enabled by default unless explicitly disabled with --no-<flag>.
+    #   - --no-transport-sse-enabled # Disable legacy SSE endpoints (/sse and /messages/)
+    #   - --no-transport-streamable-http-enabled #  Disable Streamable HTTP transport (/mcp endpoint)
+    #   - --no-json-response # Disable JSON response mode in Streamable HTTP transport (instead of SSE over HTTP)
     container_name: ragflow-server
     ports:
       - ${SVR_HTTP_PORT}:9380
       - ../history_data_agent:/ragflow/history_data_agent
       - ./service_conf.yaml.template:/ragflow/conf/service_conf.yaml.template
       - ./entrypoint.sh:/ragflow/entrypoint.sh
-
     env_file: .env
     environment:
       - TZ=${TIMEZONE}

docker/entrypoint.sh

 MCP_SCRIPT_PATH="/ragflow/mcp/server/server.py"
 MCP_MODE="self-host"
 MCP_HOST_API_KEY=""
+MCP_TRANSPORT_SSE_FLAG="--transport-sse-enabled"
+MCP_TRANSPORT_STREAMABLE_HTTP_FLAG="--transport-streamable-http-enabled"
+MCP_JSON_RESPONSE_FLAG="--json-response"
 
 # -----------------------------------------------------------------------------
 # Host ID logic:
       MCP_SCRIPT_PATH="${arg#*=}"
       shift
       ;;
+    --no-transport-sse-enabled)
+      MCP_TRANSPORT_SSE_FLAG="--no-transport-sse-enabled"
+      shift
+      ;;
+    --no-transport-streamable-http-enabled)
+      MCP_TRANSPORT_STREAMABLE_HTTP_FLAG="--no-transport-streamable-http-enabled"
+      shift
+      ;;
+    --no-json-response)
+      MCP_JSON_RESPONSE_FLAG="--no-json-response"
+      shift
+      ;;
     --consumer-no-beg=*)
       CONSUMER_NO_BEG="${arg#*=}"
       shift
         --port="${MCP_PORT}" \
         --base-url="${MCP_BASE_URL}" \
         --mode="${MCP_MODE}" \
-        --api-key="${MCP_HOST_API_KEY}" &
+        --api-key="${MCP_HOST_API_KEY}" \
+        "${MCP_TRANSPORT_SSE_FLAG}" \
+        "${MCP_TRANSPORT_STREAMABLE_HTTP_FLAG}" \
+        "${MCP_JSON_RESPONSE_FLAG}" &
 }
 
 # -----------------------------------------------------------------------------

mcp/server/server.py

     print(f"MCP port: {PORT}", flush=True)
     print(f"MCP base_url: {BASE_URL}", flush=True)
 
+    if not any([TRANSPORT_SSE_ENABLED, TRANSPORT_STREAMABLE_HTTP_ENABLED]):
+        print("At least one transport should be enabled, enable streamable-http automatically", flush=True)
+        TRANSPORT_STREAMABLE_HTTP_ENABLED = True
+
     if TRANSPORT_SSE_ENABLED:
         print("SSE transport enabled: yes", flush=True)
         print("SSE endpoint available at /sse", flush=True)