refactor(plugins/anthropic): migrate plugin to v2 API (#347)

* refactor(plugins/anthropic): migrate plugin to v2 API

* fix(plugins/anthropic): test

* refactor(plugins/anthropic): remove 'anthropic' prefix

* fix(plugins/anthropic): couple issues with migrations

* fix: broken test

* fix(plugins/anthropic): add prefix

* fix(plugins/anthropic): fix broken test

* fix(plugins/anthropic): resolver

* feat(plugins/anthropic): pull list of models from anthropic SDK

* refactor(plugins/anthropic): improve list func readability

* fix(plugins/anthropic): prefix and adjust based on feedback

* fix(plugins/anthropic): test

* feat(anthropic): add sonnet 4.5

* fix(anthropic): export sonnet 4.5

* fix(anthropic): remove accidentally committed stuff

Author: CorieW