feat: make docs output path configurable via user settings

[minsoo-web]

Problem

Projects that already use docs/ for their own documentation (specs, API docs, etc.) experience path conflicts when compound-engineering auto-generates and references files under the same docs/ directory. This creates ambiguity about what is project-owned vs plugin-generated content.

Proposal

Allow users to configure the output path for plugin-generated documents (brainstorms, plans, solutions, specs) via a global or project-level setting — similar to how other paths are already configurable.

Example:

{
  "compound-engineering": {
    "docsPath": ".compound/docs"
  }
}

This would redirect all auto-generated reads/writes from docs/ to the configured path.

Why it matters

• docs/ is a widely used convention (VitePress, Docusaurus, API docs, etc.)
• Mixing project docs with plugin-generated artifacts makes both harder to navigate
• A simple path override keeps the default ergonomic while unblocking projects that need separation

[jong-kyung]

Same here.

[ApolonTorq]

Tentative suggestion: may even be worth having a different default?
For example:

.compound/

[mattjefferson]

Either way we would still want to use docs/ whether it is the default or we have to set it. It seems a lot of other skills (external and internally developed) use docs as the landing spot and we use it to coordinate with those other skills

[tmchow]

This is a great idea and something I'm in progress of tackling to try to make this configurable and skill to help setup. Stay tuned!