Reverts the Content-Type middleware and custom server/mux plumbing from #149, keeping only the `http.ErrServerClosed` fix which is a legitimate bug.
The middleware is unnecessary because rmcp's `post_message` already returns early for 202/204 before any Content-Type validation. Both Go MCP SDKs (`modelcontextprotocol/go-sdk` used by GitHub's MCP server, and `mark3labs/mcp-go` used here) intentionally omit Content-Type on 202 responses per the MCP spec. See #148 for the full analysis.
*PR written by Claude on behalf of @silverwind*
Reviewed-on: https://gitea.com/gitea/gitea-mcp/pulls/150
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-committed-by: silverwind <me@silverwind.io>