docs: supersede the legacy workflow engine

docs/adr/0004-bun-extension-workspaces-01SEP2026.md

@@ -8,7 +8,7 @@ Publish packages to the `jb` owner endpoint of the Gitea npm registry. Repositor
 
 `extensions/shared` is the publishable `@jbcode/pi-shared` library. Extensions that import it declare a normal runtime dependency so Pi's production package installation receives the required code.
 
-`extensions/_workflows` is reference code, not a package or publishable extension. `@jbcode/pi-workflow` remains a private workspace until the required reference runtime is merged under `extensions/workflow`; this prevents publishing two workflow packages or publishing an incomplete package.
+`extensions/_workflows` is reference code, not a package or publishable extension. The package-boundary decision remains valid, but [ADR 0006](./0006-skill-led-development-workflow-04SEP2026.md) supersedes the proposed runtime merge: `@jbcode/pi-workflow` now remains private, unpublished, and unexposed as historical pilot evidence.
 
 The existing `config/pi-links.json` policy remains the authority for live-development exposure. Package boundaries and publication do not automatically enable extensions globally.
 
@@ -18,4 +18,4 @@ The existing `config/pi-links.json` policy remains the authority for live-develo
 - Catalog and workspace protocols require `bun publish` or `bun pm pack` before npm publication so concrete versions are written into package metadata.
 - Shared libraries must be published before extensions that depend on the same new version.
 - Pi packages continue shipping TypeScript source because Pi loads extension entrypoints directly.
-- The `workflow` merge is an explicit blocker for its first release.
+- ADR 0006 removes a `workflow` extension release from the active plan; archival or removal follows the skill pilot.