Add the ability to filter tools based on token scopes for PAT users.
This uses an HTTP HEAD request to GitHub's API to discover token scopes.
New components:
- pkg/scopes/filter.go: HasRequiredScopes checks if scopes satisfy tool requirements
- pkg/scopes/fetcher.go: FetchTokenScopes gets scopes via HTTP HEAD to GitHub API
- pkg/github/scope_filter.go: CreateScopeFilter creates inventory.ToolFilter
Integration:
- Add --filter-by-scope flag to stdio command (disabled by default)
- When enabled, fetches token scopes on startup
- Tools requiring unavailable scopes are hidden from tool list
- Gracefully continues without filtering if scope fetch fails (logs warning)
This allows the OSS server to have similar scope-based tool visibility
as the remote server, and the filter logic can be reused by remote server.