Insufficient-permission errors now classified as 'not_permitted'

What

• When a server responds with a 403 error whose body contains the code oauth_scope_insufficient, Claude Code now classifies it specifically as not_permitted (with an errorCode of oauth_scope_insufficient) instead of treating it as a generic HTTP error.
• When fetching the marketplace/plugin catalog fails for this not_permitted reason, Claude Code now records a servedCatalogNotPermitted flag and short-circuits to using the cached catalog only, instead of retrying the network fetch.
• Error results throughout this path can now carry an optional errorCode field.

Why

Before this change, a permissions problem could look like a generic network failure and cause Claude Code to keep retrying a fetch that was never going to succeed. Recognizing the specific 'not permitted' case lets it fail fast and fall back to cached data instead.