Recon workspace pipeline: document and test the contributor path for adding a new stage

[mswell]

Parent

• PRD: Deepen the Recon Workspace Pipeline #29

What to build

Document and test the contributor path for adding a new recon workspace pipeline stage. After the main stage families have been deepened, contributors should have a simple pattern for adding a new stage contract without scattering validation, diagnostics, output declarations, dry-run rendering, or command adapter behavior across shallow modules.

This slice should apply the deletion test: the recon workspace pipeline module should concentrate enough behavior that deleting it would re-spread real complexity across callers.

Acceptance criteria

• Contributor-facing documentation or an in-repo example explains how to add a new recon stage contract using the domain vocabulary.
• A small test fixture or representative stage proves new stages can declare inputs, outputs, diagnostics, and dry-run behavior through one pipeline seam.
• The guidance preserves existing user-facing shell function names and current artifact names by default.
• Tests verify external behavior at the recon workspace pipeline interface rather than incidental helper layout.
• The implementation avoids turning the pipeline interface into a shallow facade; validation, diagnostics, output declaration, and dry-run rendering remain concentrated behind it.
• No network-dependent recon tools run in default tests.

Blocked by

• Recon workspace pipeline: prove the contract seam with workspace and passive enumeration stages #61
• Recon workspace pipeline: deepen live-host stages with shared validation and artifact categorization #62
• Recon workspace pipeline: make crawling and JavaScript collection diagnosable #63
• Recon workspace pipeline: unify Nuclei scan diagnostics behind the stage interface #64
• Recon workspace pipeline: add infrastructure enrichment stage contracts #65