docs: document include manifest field, loader pre-check, and helper scripts

[stack72]

Summary

Documents the include manifest field and loader pre-check behaviour introduced in #849.

Changes

design/extension.md

• Added include to manifest Optional Fields section with description
• Added explanation of include files in the Models section (copied to archive under models/, not bundled)
• Added new "Loader pre-check" section explaining how loaders skip files without the expected export

swamp-extension-model/SKILL.md

• Added Key Rule 5: "Helper scripts" — use include for files executed via Deno.Command subprocess, links to examples

swamp-extension-model/references/examples.md

• Added "Helper Scripts" to table of contents
• Added complete example showing: manifest with include, model that shells out to helper, helper script with native deps that isn't bundled

swamp-extension-model/references/publishing.md

• Updated "What Happens During Push" steps to include:
  • Step 5: Resolve include files
  • Step 6: Safety analysis now explicitly includes include files
  • Step 7: Quality checks explicitly exclude include files
  • Step 8: Bundle step notes include files are not bundled

🤖 Generated with Claude Code

[github-actions]

Code Review

Documentation-only PR — verified all documented behavior against the actual codebase.

Blocking Issues

None.

Suggestions

1. Minor: Loader pre-check docs could mention all loader types — design/extension.md says loaders check for "the expected named export (export const model, export const vault, etc.)" which is accurate but slightly vague. All five loaders (model, vault, driver, datastore, report) implement the same pre-check pattern. The current wording with "etc." is fine, but listing them explicitly could be more precise. Not blocking since the pattern is clear.

2. Minor: Example execute signature — In the helper scripts example in examples.md, the execute callback uses (_args: unknown, context: { repoDir: string }). The _args: unknown typing is consistent with Key Rule 7 ("No type annotations — avoid TypeScript types in execute parameters"), but it might be worth noting in a comment that the inline context type is just for illustration since real context comes from the runtime. Very minor — the example is clear as-is.

All documented behavior (include file resolution relative to modelsDir, safety analysis inclusion, quality check exclusion, archive placement under models/, loader pre-check regex) matches the implementation. Good docs update.