*Title*: MCP: mcp_json_rest_bridge filter progress *Description*: This is the issue to track the implementation progress for new the mcp_json_rest_bridge filter. [optional *Relevant Links*:] Past PRs: https://github.com/envoyproxy/envoy/pull/43575 https://github.com/envoyproxy/envoy/pull/43742 https://github.com/envoyproxy/envoy/pull/43937 https://github.com/envoyproxy/envoy/pull/44014 https://github.com/envoyproxy/envoy/pull/44133
