doctor: split provider/model refs on the first slash

[xRahul]

Refs #697

The hidden-agent catalog check parsed "provider/model" with split("/", 2), so model ids that themselves contain slashes (OpenRouter serves ids like openrouter/free and dots-studio/dots-3-note-preview:free) became a bogus provider/model pair and were wrongly reported as not offered by the host. Split on the first slash only, matching the [provider, ...modelParts] idiom used elsewhere in the repo, and cover both the unknown-model and unknown-variant checks with tests.

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Summary by cubic

Fixes the doctor command parsing of provider/model references so model IDs that themselves contain slashes (for example OpenRouter's openrouter/free or dots-studio/dots-3-note-preview:free) are no longer split into bogus provider/model pairs and wrongly reported as not offered by the host.

• Splits provider and model on the first slash only, matching the [provider, ...modelParts] idiom used elsewhere in the repo.
• Adds tests covering both the unknown-model and unknown-variant checks with slash-containing model IDs.

^{Written for commit f571812. Summary will update on new commits.}

Confidence Score: 5/5

This PR appears safe to merge.

Summary

Doctor now keeps everything after the first slash when checking configured OpenCode models and variants.

• OpenCode doctor keeps slashes inside model IDs when checking the host catalog.

_{Reviews (1) · Last reviewed commit: "doctor: split provider/model refs on the..." · Reviewed by Greptile}

[github-actions]

#697 has the design-approved label; this PR can be reviewed.

[cubic-dev-ai]

No issues found across 2 files

_{View guided diff | Re-trigger cubic}

[magic-alfonso]

Thanks @xRahul! Merged as 03b5ba5. doctor now splits provider/model references only at the first slash, so OpenRouter models whose names contain a slash are no longer reported as missing. It ships in the next release, and I'll post on issue 697 when it's out.