support new searchPackages endpoint

[drernie]

Expose a high-level interface like:

# api/python/quilt3/admin/packages.py
def search(buckets=None, search_string=None, filter=None, user_meta_filters=None, latest_only=False):
    client = util.get_client()
    result = client.search_packages(
        buckets=buckets,
        search_string=search_string,
        filter=filter,
        user_meta_filters=user_meta_filters,
        latest_only=latest_only
    )
    return result

[drernie]

Based on the existing pattern, adding package search queries would generate:

• search_packages.py: Contains SearchPackagesQuery class with typed input/output
• search_more_packages.py: Contains SearchMorePackagesQuery class
• Additional type files: For PackagesSearchResultSet, PackagesSearchFilter, etc.
• Updated client.py: With search_packages() and search_more_packages() methods

[drernie]

Configuration: There's likely a pyproject.toml or configuration file that defines:

• GraphQL schema source (the enterprise registry's schema)
• Output directory (api/python/quilt3/admin/_graphql_client/)
• Base client configuration
• Generation Command: The generation process would be something like: cd api/python/quilt3-admin && ariadne-codegen