v0.12.0

Added

• A repo can be both a Claude plugin marketplace and a mind curator. A bare
  [discover].sources list in a co-present mind.toml composes with a
  .claude-plugin/marketplace.json (or plugin.json) instead of suppressing it:
  the manifest defines the repo's own items and the curated chain layers on top
  (MKT-16). New marketplace-curator example.

Changed

• An own-item source-discovery directive now suppresses only a co-present
  .claude-plugin/ manifest's own-item layer, and the set of such directives is
  broadened. A mind.toml [source].roots/flat-skills, or a consumer meld --root/--flat-skills flag, suppresses the manifest and runs convention
  discovery instead (with a note), so --root is no longer a silent no-op on a
  manifest source (MKT-15).