v5.3.0

The DevX surprise swarm ran ten personas over the full create-to-release
journey and ranked five blocker clusters. All five land here.

Added

• extension_release_list: the discovery sibling of the release verbs.
  Lists the project's channels (channel to promoted build sha) and recent
  builds from the public registry (registry.extension.land), so a caller
  can pick a valid buildSha for extension_release_promote,
  extension_deploy, or extension_publish instead of hunting the
  console. Read-only, needs no auth for public projects. Tool count is
  now 32.
• A shared public-registry client (src/lib/registry.ts) that reads
  meta, channels, the build index, and store credential health. Reads
  are best-effort: a registry blip never fails the verb it decorates.

Fixed

• extension_create announces every decision it took without being
  asked. The resolved destination path leads the result, and
  defaultsApplied names each silent choice (server cwd, package
  manager, browser, git init) as one. Validation errors now teach the
  full argument schema, required, optional, and aliases, instead of
  revealing one missing field per attempt.
• extension_dev no longer forks sessions. A second call on the same
  projectPath used to return ok:true while its browser died on the
  profile lock; it now detects the live session and refuses, or stops it
  first with replace:true and says so. A dead browser leg no longer
  rides an ok:true envelope: the ready contract's browser_exited stamp
  and the profile-lock signature both surface as failures.
• extension_stop finds orphaned sessions. It unions the in-memory
  registry with the on-disk session markers, so a session whose dev
  child exited (exactly when the orphaned browser most needs stopping)
  is still found, verified, and reaped. A stale marker yields an honest
  stopped:false and is pruned, never a phantom kill.
• extension_deploy dry runs stopped echoing an unqualified
  "Preflight OK". The preflight now reads per-store credential health
  from the registry and reports each browser as actionable, not
  configured, or unverifiable, with the console stores URL in the
  result. The silently defaulted channel is disclosed and checked
  against channels.json. Under dryRun a platform error now reads
  "preflight failed", never "submit failed".
• extension_release_promote dead-ends carry the way out: a 404 or
  UNKNOWN_BUILD error now includes each channel's currently promoted
  sha, the registry URL it read, and the console Builds page URL, plus
  a pointer to extension_release_list.
• extension_publish says what the share link serves: the build sha,
  build time, version, and channel behind the URL, resolved from the
  registry's build index, with a note when it is the newest successful
  build rather than a pinned one.