refactor: remove SSE transport support from code and documentation (#97)

- Remove support and documentation for sse mode across all language README files
- Update CLI flags and help text to exclude references to sse mode
- Remove SSE server initialization in operation logic
- Adjust error messages to only mention stdio and http transport types
- Update logging setup to remove sse mode conditional logging

See the latest documentation: https://modelcontextprotocol.io/specification/2025-06-18/basic/transports

Signed-off-by: appleboy <appleboy.tw@gmail.com>

Reviewed-on: https://gitea.com/gitea/gitea-mcp/pulls/97
Co-authored-by: appleboy <appleboy.tw@gmail.com>
Co-committed-by: appleboy <appleboy.tw@gmail.com>

README.zh-tw.md

@@ -133,21 +133,6 @@ cp gitea-mcp /usr/local/bin/
 }
 ```
 
-- **sse 模式**
-
-```json
-{
-  "mcpServers": {
-    "gitea": {
-      "url": "http://localhost:8080/sse",
-      "headers": {
-        "Authorization": "Bearer <your personal access token>"
-      }
-    }
-  }
-}
-```
-
 - **http 模式**
 
 ```json
@@ -221,10 +206,10 @@ Gitea MCP 伺服器支持以下工具：
 
 ## 🐛 調試
 
-要啟用調試模式，請在使用 sse 模式運行 Gitea MCP 伺服器時添加 `-d` 旗標：
+要啟用調試模式，請在使用 http 模式運行 Gitea MCP 伺服器時添加 `-d` 旗標：
 
 ```sh
-./gitea-mcp -t sse [--port 8080] --token <your personal access token> -d
+./gitea-mcp -t http [--port 8080] --token <your personal access token> -d
 ```
 
 ## 🛠 疑難排解