Generated enums repeat values under _1 names (19 enums on 10.0.0b4, 17 on 9.3.0) #1782

Codegen emits some StrEnums with the same value twice, under a second name ending in _1. For example, postal_country_system.System has zip = 'zip' and zip_1 = 'zip', and display_tag_asset.Field17 has ad_request_url_1 = 'ad_request_url'. Python turns the second member into an alias of the first. So nothing breaks at runtime, but:

• autocomplete, docs and __members__ offer names that are not AdCP values;
• code that switches on a member name (or serializes member.name) can see zip_1;
• the duplicates suggest the generator merges overlapping enum lists from sibling anyOf arms without deduplicating them.

Repro

import importlib
import pkgutil
from enum import Enum

import adcp.types.domains as domains

seen: dict[str, list[str]] = {}
for module_info in pkgutil.walk_packages(domains.__path__, domains.__name__ + "."):
    try:
        module = importlib.import_module(module_info.name)
    except ImportError:  # tombstone modules for removed types
        continue
    for name, obj in vars(module).items():
        if isinstance(obj, type) and issubclass(obj, Enum) and obj.__module__ == module.__name__:
            aliases = [alias for alias, member in obj.__members__.items() if alias != member.name]
            if aliases:
                seen[f"{module.__name__}.{name}"] = aliases

print(len(seen), "enums with duplicate values")

10.0.0b4 prints 19, including:

adcp.types.domains.core.assets.asset_union.Field1 ['ad_request_url_1', 'clickthrough_url_1']
adcp.types.domains.core.assets.display_tag_asset.Field17 ['ad_request_url_1', 'clickthrough_url_1']
adcp.types.domains.core.postal_area.System ['zip_1', 'zip_plus_four_1']
adcp.types.domains.core.postal_area.System1 ['outward_1', 'full_1']
adcp.types.domains.core.postal_area.System2 ['fsa_1', 'full_1']

9.3.0 prints 17 (the postal-system enums).

Suggested fix

Deduplicate enum values when codegen merges value lists, and add a codegen check that fails when a generated enum has an alias.