Add ergonomic aliases for control-plane methods

[njbrake]

Summary

• The control-plane resources previously exposed only the OpenAPI-generator-derived method names (e.g. keys.create_key_v1_keys_post(...)), leaking generator naming into the public management surface. The migrated shell explicitly flagged friendlier aliases as a follow-up.
• Each resource accessor (keys, users, budgets, pricing, usage) now returns a hand-written wrapper exposing ergonomic aliases that delegate to the generated methods:
  • keys: create, get, list, update, delete
  • users: create, get, list, update, delete, get_usage
  • budgets: create, get, list, update, delete
  • pricing: get, set, delete, get_history, list
  • usage: list
• The generated core is untouched, so regeneration is unaffected. The raw generated methods stay reachable via a raw accessor on each resource (e.g. keys.raw.create_key_v1_keys_post(...)) as an escape hatch.
• Aliases forward request options (_request_timeout, _headers, ...) through **kwargs.

Test plan

• ruff check .
• mypy src/
• New unit test (tests/unit/test_control_plane_aliases.py): table-driven assertions that every alias forwards to the correct generated method with the right args, options pass through as kwargs, and raw exposes the generated API.
• Integration tests rewritten to drive the ergonomic aliases, plus a new test proving the raw escape hatch works end to end.
• Full suite: 116 passed, 2 skipped, including the 7 control-plane integration tests run against a live gateway built from the otari repo.

Fixes #107

🤖 Generated with Claude Code