Feature Request: Support mounting r2 bucket contents into Workspace

Filing this as a reminder for @threepointone after our brief discussion on twitter as requested https://x.com/simonxabris/status/2054268963668828481?s=20

I have a bunch of documents in r2, I want to create an mcp where users can search in these via a codemode mcp

Ideally, I should be able to do this by mounting the contents of this bucket, with an optional path prefix, into a shell `Workspace` and then just use shell and codemode as intended in an mcp.

My current workaround is i created a worker that has access to a sandbox, on an mcp request i copy the r2 contents into the sandbox. I expose a `code` tool through my mcp server and run the code the mcp client generates in this sandbox that has the r2 files. It works, but requires lot of plumbing.