The previous commit generated plugin.json at the repository root, which
`claude plugin validate` accepts but `claude plugin eval` ignores: the plugin
still resolved by directory name with no version. Only
.claude-plugin/plugin.json sets the name and version.
Adds an optional per-target pluginManifestFile (plugin.json or
.claude-plugin/plugin.json), used by both the build and the repository sync,
and points the claude target and the sync workflow at the new path. Kiro is
unchanged.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>