### What problem does this PR solve?
0.18.0 mcp server can not start with upgrade from 0.17.2 or new install
except rebuild all docker

Close #7321

mcp server can not start auto from docker :
2025-04-25 17:30:44,512 INFO 25 task_executor_2a9f3e2de99a_0 reported
heartbeat: {"name": "task_executor_2a9f3e2de99a_0", "now":
"2025-04-25T17:30:44.509+08:00", "boot_at":
"2025-04-25T16:43:33.038+08:00", "pending": 0, "lag": 0, "done": 0,
"failed": 0, "current": {}}
usage: server.py [-h] [--base_url BASE_URL] [--host HOST] [--port PORT]
                 [--mode MODE] [--api_key API_KEY]
server.py: error: unrecognized arguments:

problem:
server.py in docker start arguments not correct , so mcp server start
fail
reason:
```
1. docker-copose.yaml
     example  - --mcp-host-api-key="ragflow-12345678" is wrong.  do not add "" to key or it says:"api-key wrong"
2.docker file  entrypoint.sh  can not translate config to exec command , we need mapping file from host to docker
     - ./entrypoint.sh:/ragflow/entrypoint.sh
3.just add one code raw fix all probelm 
```
### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] Documentation Update
- [x] Performance Improvement

---------

Co-authored-by: Yongteng Lei <yongtengrey@outlook.com>
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

### What problem does this PR solve?

This PR fixes an issue with the MCP server configuration in RAGFlow's
Docker deployment where:
1. Incorrect parameter naming (`--mcp--host-api-key` with double
hyphens) caused server startup failures
2. Port binding conflicts occurred due to unexposed MCP ports in Docker
3. Inconsistent host addressing between `0.0.0.0` and `127.0.0.1` led to
connectivity issues

The changes ensure proper MCP server initialization and reliable
inter-service communication.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [ ] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):

### Key Changes

1. **Parameter Correction**:
   - Fixed `--mcp--host-api-key` → `--mcp-host-api-key`

### What problem does this PR solve?

update for v0.18.0

### Type of change

- [x] Documentation Update

### What problem does this PR solve?


### Type of change


- [x] Documentation Update

### What problem does this PR solve?

Add mcp self-host mode documentation, a complement of #7141.

### Type of change

- [x] Documentation Update

---------

Co-authored-by: writinwaters <93570324+writinwaters@users.noreply.github.com>

### What problem does this PR solve?

Documentation for MCP server

### Type of change

- [x] Documentation Update

---------

Co-authored-by: writinwaters <93570324+writinwaters@users.noreply.github.com>