#14579: docs: add guide for openclaw-bridge-remote (MCP)

## Summary This PR adds a documentation guide for **openclaw-bridge-remote**, an MCP bridge that enables remote AI agents to control local OpenClaw instances. ### Changes - Added `docs/gateway/mcp-bridge.md`: A quick-start guide for the bridge. - Updated `docs/docs.json`: Added the new guide to the 'Infrastructure' sidebar. ### Context Many developers use OpenClaw on their local machines but develop primarily on remote GPU clusters or cloud instances. This bridge fills the gap by providing a secure, MCP-native way to delegate browser and shell tasks to the local machine from a remote agent. <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> Adds a new Mintlify doc page (`docs/gateway/mcp-bridge.md`) describing how to use the `openclaw-bridge-remote` MCP bridge to connect remote AI agents to a local OpenClaw gateway, and wires the page into the Infrastructure → Remote access and deployment sidebar via `docs/docs.json`. The guide includes a mermaid architecture diagram, a quick-start install command, and an example MCP server config snippet for remote agent clients. <h3>Confidence Score: 4/5</h3> - This PR is mostly safe to merge, but the new doc contains a formatting typo and promotes an unsafe installation pattern. - Changes are limited to documentation and sidebar navigation, with no runtime impact. Two doc issues should be addressed: a stray quote that will break rendering, and a `curl | bash` one-liner that’s inappropriate for official security-sensitive documentation. - docs/gateway/mcp-bridge.md <!-- greptile_other_comments_section --> _{(2/5) Greptile learns from your feedback when you react with thumbs up/down!} <!-- /greptile_comment -->