Document embeds Phases 2-5: snapshots, delta, CI, diagnostics/matrix

[avrabe]

Context

After Phase 1 is complete, the remaining phases can be executed in parallel.

Spec: docs/superpowers/specs/2026-03-29-document-embeds-design.md

Phases (after Phase 1)

Phase 2: Snapshots and delta (independent)

• rivet snapshot command — dumps stats/coverage/diagnostics to JSON
• rivet snapshot diff subcommand — compares current vs baseline
• delta=BASELINE option on {{stats}} and {{coverage}} embeds
• Dashboard delta columns (stats, coverage, validation pages)
• Config: snapshots: section in rivet.yaml
• SC-EMBED-2 (git commit in snapshot), SC-EMBED-6 (schema version compat)

Phase 3: CI automation (depends on Phase 2)

• Release snapshot workflow (on tag push → auto-commit snapshot)
• PR delta comment workflow (sticky comment with traceability delta)
• Auto-snapshot sidecar on rivet export

Phase 4: AI agent guide + STPA artifacts (independent)

• /api/v1/guide endpoint (depends on PR feat(api): oEmbed provider and Grafana JSON API endpoints #89 being merged)
• rivet guide CLI with --format json
• Enhanced help pages (how-to-create, common mistakes)
• LSP suggestion diagnostics
• STPA artifacts: L-EMBED-, H-EMBED-, UCA-EMBED-, SC-EMBED-
• SC-EMBED-5, SC-EMBED-7

Phase 5: Diagnostics + matrix embeds (independent)

• {{diagnostics}} embed with severity filter and NEW/RESOLVED badges
• {{matrix}} inline traceability matrix embed
• rivet embed CLI for programmatic access to all embed types

Parallel execution

Phase 1 → (Phase 2 + Phase 4 + Phase 5 in parallel) → Phase 3