feat: add Claude Opus 4.7 model support

[allen-moonshot]

Summary

• Add claude-opus-4-7 model support
• Add 4-7 model override in model-config.ts with effort-2025-11-24 beta (matching existing 4-6 pattern)
• Update README supported models table (15 → 16 models)
• Extend test coverage in betas.test.ts for opus 4.7: 1M context eligibility, effort beta inclusion, disableEffort exclusion, and default context-1m opt-out

All existing tests pass (213/213). Build, lint, and format clean.

Using 4.7 before OpenCode ships it

The plugin only handles auth and beta flags — model discovery lives in OpenCode's Anthropic provider config. Until OpenCode adds claude-opus-4-7 to their SDK, users can register it manually in their opencode.json:

```json
{
"provider": {
"anthropic": {
"models": {
"claude-opus-4-7": { "name": "Claude Opus 4.7" }
}
}
}
}
```

Tested end-to-end against Anthropic's API with an active Claude Max subscription — plugin applies the correct betas (effort-2025-11-24, plus context-1m-2025-08-07 when opted in) and requests complete successfully.

Happy to add this snippet to the README in a follow-up (or here) if you'd like — left it out of the initial diff to keep the PR focused on plugin-side config.

[griffinmartin]

Sonnet 4.7 doesn't exist yet to my understanding.

[allen-moonshot]

Good catch — you're right, only Opus 4.7 is live on the API. Removed Sonnet 4.7 from the README, tests, and updated the PR title/description. Opus 4.7 verified working end-to-end with the 4-7 override (effort beta + 1M context when opted in).

[boring-dragon]

Its out now

[griffinmartin]

[griffinmartin]

models.dev just had 4.7 added, so the manual opencode.json change shouldn't be required much longer.
opencode models --refresh

[soltrac]

Not sure if possible. Some frameworks send temperature to the models but opus 4.7 has deprecated it. Is it possible to filter this from this plugin?