[Feat] Add GLM 5.3 support to Z AI and OpenCode Go

[zoomote]

​Opened on behalf of @taltas. Follow up by mentioning @roomote, in the web UI, or in Discord.

What changed

• Added glm-5.3 to the native Z AI provider for both International Coding and China Coding Plan entrypoints while keeping it unavailable on the standard pay-as-you-go API entrypoints.
• Added its 1M context window, 128K output limit, required Low/High/Max reasoning with Max as the default, prompt-cache support, configurable output limit, and reasoning preservation.
• Applied GLM-5.2 pricing provisionally as requested: $1.40 input / $0.26 cached input / $4.40 output internationally, and $0.68 / $0.13 / $2.28 for China mainland.
• Kept the existing OpenCode Go catalog support and LiteLLM reasoning preservation, with tests covering endpoint filtering, regional metadata, standard API fallback, pricing, runtime request behavior, and selector normalization.

Why this change was made

GLM-5.3 is released for all Z AI Coding Plan subscribers even though Z AI's standard API rollout and official per-token prices are still pending. The provider catalogs now match that phased availability instead of limiting support to OpenCode Go or exposing an unsupported standard API route.

Impact

Z AI Coding Plan and OpenCode Go users can select GLM-5.3 with accurate limits and reasoning controls. Existing disabled reasoning settings are normalized to Max because GLM-5.3 requires reasoning, while standard API users continue to see only models officially available on those endpoints.

Related PRs

• Zoo Code documentation

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[zoomote]

Fixed both failing Codecov patch checks in commit 61fc770f3. Added focused hook coverage for the default International Coding catalog, China Coding GLM-5.3 metadata, and fallback when GLM-5.3 is unavailable on the standard International and China API endpoints. Both codecov/patch checks and the full GitHub CI suite now pass.