feat(providers): offer Qwen3.8 Max on Alibaba Coding Plan once Alibaba lists it

[me2seeks]

Summary

Qwen3.8 Max (qwen3.8-max) is not selectable for Alibaba Coding Plan (China) / Alibaba Coding Plan connections. This currently matches Alibaba's official plan allowlist, so Maka is behaving as designed — this issue tracks adopting the model once Alibaba adds it to the Coding Plan.

Evidence (checked 2026-08-20)

• Maka's allowlist is alibabaCodingPlanModelIds in packages/core/src/provider-registry.ts; the code declares Alibaba's Coding Plan docs authoritative for it.
• Alibaba's Coding Plan docs (CN / Global) publish an exact-string allowlist: qwen3.7-plus, qwen3.6-plus, kimi-k2.5, glm-5, MiniMax-M2.5, qwen3.5-plus, qwen3-max-2026-01-23, qwen3-coder-next, qwen3-coder-plus, glm-4.7 — qwen3.8-max is not listed.
• The models.dev snapshot (Maka's metadata source) has no qwen3.8-max entry under alibaba-coding-plan-cn / alibaba-coding-plan, so re-running scripts/sync-model-metadata.mjs does not surface it either.
• Selecting an unlisted model would fail server-side with model 'qwen3.8-max' is not supported per Alibaba's Coding Plan FAQ.

Contrast: Alibaba Token Plan officially supports qwen3.8-max and was enabled in #3157 — users who need Qwen3.8 Max today can use that access path.

Adoption checklist (blocked on upstream)

1. Alibaba Coding Plan docs list qwen3.8-max as a supported exact model id.
2. models.dev publishes qwen3.8-max under alibaba-coding-plan-cn / alibaba-coding-plan; refresh via scripts/sync-model-metadata.mjs.
3. Add qwen3.8-max to alibabaCodingPlanModelIds in packages/core/src/provider-registry.ts (China and global share one list), mirroring the feat(providers): support Qwen3.8 Max on Token Plan #3157 shape: thinking-effort overrides in model-metadata.ts, catalog/thinking/wire-contract tests.