refactor(opencode-go): extends mimo models from xiaomi provider

[juls0730]

opencode go breakout commit of #1631

Notes

• Context limit changes: A number of models have had their context windows changed. According to https://opencode.ai/go the provider for MiMo models is xiaomi so context windows should be the same. Some errors propogate because a few of the models in the xiaomi root provider have context limit errors such as not rounding to powers of two
• MiMo V2 Pro Pricing: Currently the Xiaomi provider does not have the correct context_over_200k pricing

I believe these are acceptable regressions/changes as they will be fixed when I create my commit to fix all the minor bugs the xiaomi root provider has