v0.9.0

Added

• Consume Claude Code plugin manifests as a discovery source. A melded repo with
  a .claude-plugin/plugin.json (a single plugin) or .claude-plugin/marketplace.json
  (a catalog) has its skills and agents mapped to mind items and installed
  through the usual store-and-symlink path; mind never writes Claude's plugin
  cache or settings.json. The plugin name is the default namespace prefix
  (agents stay bare per NS-40); unsupported components (commands, hooks,
  .mcp.json, ...) report a skipped count on meld. A marketplace is consumed as a
  curated super-source, one sub-source per listed plugin, in-repo or external.
  Manifests are held to the same path-safety and strict-parse guards as
  mind.toml, and recall --sources labels a source's manifest origin
  (claude-plugin / claude-marketplace) (MKT-1..11).
• upgrade accepts a glob in place of an exact item ref, mirroring forget; the
  kind prefix and source qualifier compose (upgrade 'jk:*', upgrade 'skill:*', upgrade 'owner/repo#*'). A glob (or exact ref) that matches no
  installed item reports up-to-date rather than erroring (CLI-65).

Changed

• The namespace separator is : instead of -: a prefixed item installs as
  <prefix>:<name>. upgrade migrates already-installed items from the old
  <prefix>-<name> form in place, without a namespace change.
• meld --as is renamed --namespace (short -n); --as stays as a deprecated
  alias. A source's namespace is locked once any of its items are installed:
  changing it requires forgetting those items first, rather than an in-place
  rename of installed items (NS-30, CLI-161).
• Agents are no longer namespaced by a source prefix. An agent links into each
  lobe under its bare frontmatter name (the harness keys agents by that name,
  not the filename), so a prefix reaches only its store path and manifest key.
  Two sources shipping a same-named agent now collide: learn refuses with an
  AgentCollision error and meld emits an advisory warning (NS-40, NS-41,
  NS-42).