feat: add OpenWiki retrieval tools

[Brace Sproul (bracesproul)]

What changed

• Adds the OpenWiki retrieval MCP server and package binary.
• Implements repository indexing, keyword/semantic ranking, change-surface retrieval, and focused search.
• Adds retrieval-focused tests.
• Extends the generated agent guidance with instructions specific to the retrieval tools.

Why

Give coding agents concise, source-grounded repository evidence without requiring broad exploratory scans.

Dependency

Stacked on #528 so the generic prompt improvements can merge independently before the retrieval tools and their tool-specific guidance.

Validation

• 10 retrieval tests
• Typecheck
• Formatting

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[Ben (Bennoo)]

Seems great! But do i understand correctly if i say it is dedicated to other projects that needs the doc?
I mean if I have project A with an openwiki, I am working in project B that uses project A and so, needs the accurate documentation? is this related to that use case?
Thanks

[Colin Francis (colifran)]

Ben (@Bennoo) I think this is more scoped to retrieval from within a wiki scoped to a single repo.

[Ben (Bennoo)]

Great! Thanks for the clarification.
I discovered recently Mintlify (https://www.mintlify.com/) which is a documentation service exposing a MCP server for your documentation. That MCP is exposing a tool which is basically a virtual Filesystem exposing the files. I was thinking about the fact that openwiki can be tailored for that, exposing the wiki as a virtual filesystem for agents that needs to dig into the documentation from an external POV.
But maybe this is not the right place to discuss that.