task: document platforms/agents/sprig.md #1234

Parent PRD

#614

Objective

Create launchpad/docs/corpus/platforms/agents/sprig.md as the single canonical architecture component node for sprig.

Definition of done

• Exactly one hand-authored canonical corpus document is created or completed for this task; any additional changed corpus files are deterministic generated outputs only.
• The document has schema-valid front matter with a stable node ID, type, status, origin, audiences, provenance/evidence and typed relationships appropriate to the node.
• The document represents one independently maintainable knowledge node; any newly discovered second concept/contract/procedure is filed as a separate task instead of being folded into this document.
• Every substantive factual claim is traceable to current code, test, specification, accepted decision, migration/configuration, or attributed GitHub evidence; FACT, INFERENCE and TEAM KNOWLEDGE are not conflated.
• The document links relevant implementation, verification, specification/decision and neighboring corpus nodes without duplicating their canonical content.
• The draft is checked against the repository revision recorded in provenance and against Git history/PR/issues when those sources explain behavior or rationale.
• Corpus validation passes locally; no broken node IDs, invalid source paths, duplicate IDs or schema violations are introduced.
• States responsibility and well-defined interface/boundary.
• Names dependencies and collaborators.
• Links source implementation and tests.
• Explains only component-level behavior, not the entire containing platform.

Impacted components

• launchpad/docs/corpus/platforms/agents/sprig.md
• corpus generated indexes (mechanical only, if changed)

Out of scope

• Creating or materially editing a second hand-authored canonical corpus document.
• Changing runtime product behavior unless a separately linked implementation issue owns that change.
• Deciding unresolved ADR outcomes; unresolved decisions stay explicit.
• Broad “while here” documentation cleanup.

Required evidence before drafting: record the repository commit/ref; inspected source paths and symbols; tests, specifications, migrations and configuration; relevant Git history, PRs and issues; and anything expected but not verified.