[FEATURE]: Add support of Claude Opus 4.6

[AyushIIITU]

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Claude has introduced its latest model, Claude Opus 4.6, but OpenCode does not currently have this model.

[flipch]

Codex as well :)
https://x.com/OpenAI/status/2019474152743223477

[alexandrereyes]

.52 version using Anthropic Auth:

[connor-tyndall]

Yep v1.1.52 has it

[bijanmmarkes]

What about for Github Copilot Auth?

[Nepomuk5665]

got this error when going over 200k tokens: prompt is too long: 203831 tokens > 200000 maximum
activated:

[tredondo]

Yep v1.1.52 has it

I don't see it in 1.1.53 Desktop. Instead, Opus 4.5 shows twice.