Add wiki to Context, Memory & Working State

[ryanpettry]

Summary

• Add wiki to Context, Memory & Working State.
• wiki gives agents incremental access to indexed project knowledge through scoped CLI commands, deterministic indexes, linting, and merge handling for parallel edits.

Checklist

• The resource is directly relevant to harness engineering
• The link works
• The resource is not already listed
• The description explains the harness angle clearly
• The change is placed in the most appropriate section

Notes

Disclosure: I'm affiliated with the project.