Users were conflating GitHub source snapshots, CLI archives, and .gitignore behavior when debugging missing files in build outputs. This adds a small source-context note to the build configuration docs and aligns the CLI deployment page with the same distinction.

Constraint: Keep the change doc-only and directly tied to build-context troubleshooting.

Rejected: Add platform size-limit claims | no public evidence for a per-directory Railpack cap.

Confidence: medium

Scope-risk: narrow

Tested: git diff --check; pnpm exec content-collections build