fix: detect artifacts in nested workspaces

[rogerchappel]

Summary

• make default generated-output, ignored-output, cache, report, and package patterns match repository-root and nested workspace paths
• extend inferred generated/cache directory findings to nested paths
• add unit and end-to-end scanner regressions for representative monorepo outputs
• document **/ matching semantics and update the checked-in policy example

Commits

• dfb043e fix: detect generated artifacts in nested workspaces
• 3e0b9ae docs: explain nested workspace artifact patterns

Verification

• npm ci
• npm run release:check
• git diff --check
• 19 tests passed; TypeScript check/build, fixture smoke, and npm package dry run passed