v6.7.0: bundle module registry, retire marketplace, refresh display names (#2388)

* feat(installer): bundle module registry, retire marketplace, refresh display names

Prepares v6.7.0 for release:

- Moves bundled module list from tools/installer/modules/registry-fallback.yaml
  to bmad-modules.yaml at repo root; renames to reflect single-source-of-truth role.
- Retires the remote marketplace registry fetch in ExternalModuleManager; the
  installer now reads the bundled YAML only.
- Adds WDS (Whiteport Design Studio) entry alongside BMM, BMB, BMA, CIS, GDS, TEA.
- Refreshes display names and descriptions on every bundled module; TEA
  repositioned after BMM in the picker.
- Adds plugin_name override field on registry entries so modules whose
  marketplace.json declares a plugin under a different name than the installer
  code (e.g. WDS uses bmad-wds) match without falling back to the single-plugin
  heuristic.
- Removes the community modules picker from the interactive installer; previously
  installed community modules are preserved on update and can still be installed
  via --custom-source.
- Renames the custom-source confirm prompt for clarity.

CHANGELOG.md updated with the full v6.7.0 entry.

* feat(installer): fully retire community catalog plumbing

Removes the last marketplace network connections from the installer.
The v6.7.0 first pass retired the official-registry fetch but left
CommunityModuleManager + RegistryClient in place, which still
fetched community-index.yaml and categories.yaml on every install
to support the channel-gate and update flows.

This commit:

- Deletes tools/installer/modules/community-manager.js and
  registry-client.js entirely.
- Strips CommunityModuleManager calls from ui.js (channel gate +
  update channels), core/manifest.js (getModuleVersionInfo),
  core/installer.js (resolution + installed-modules listing), and
  modules/official-modules.js (findModuleSource fallback +
  pre-install plugin resolution + post-install manifest entry).
- Simplifies installFromResolution: community branch removed; all
  non-external installs are now treated as custom-source.
- Removes corresponding test suites (CommunityModuleManager unit
  tests and the entire RegistryClient suite).
- Updates CHANGELOG with the migration note.

After this commit, grep confirms zero references to the bmad-plugins-
marketplace registry from the installer. The only remaining 'marketplace'
references are about per-repo .claude-plugin/marketplace.json files,
which the installer reads from cloned custom-source repos.