* plugins: include resolved workspaceDir in provider hook cache keys
resolveProviderPluginsForHooks, resolveProviderPluginsForCatalogHooks, and
resolveProviderRuntimePlugin used the raw params.workspaceDir for cache keys
and plugin-id discovery while resolvePluginProviders already fell back to
the active registry workspace. Resolve workspaceDir once at the top of each
function so cache keys, candidate filtering, and loading all use the same
workspace root.
* fix(plugins): inherit runtime workspace for snapshot loads
* test(gateway): stub runtime registry seam
* fix(plugins): restore workspace fallback after rebase
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Co-authored-by: Vincent Koc <vincentkoc@ieee.org>
