[Feat] Add Alibaba Qwen inference providers

[roomote-roomote]

Opened on behalf of Matt Rubens. Follow up by mentioning @roomote, in the web UI, or in Slack.

What changed

• Added first-class Alibaba Cloud Model Studio, Alibaba Coding Plan, and Alibaba Token Plan inference connections.
• Added International and China region selection for each connection while keeping stable alibaba/, alibaba-coding-plan/, and alibaba-token-plan/ model IDs.
• Routed all six OpenCode endpoint variants through Roomote's credential-protecting inference gateway and forwarded the matching self-hosted environment variables.
• Applied the selected regional endpoint to direct control-plane OpenCode calls used for routing, titles, and summaries.
• Added contextual setup guidance, public provider documentation, and international/China proxy coverage.

Why this change was made

OpenCode already supports Alibaba's metered and plan-based Qwen endpoints, but Roomote did not expose them as configurable inference providers. This adds the same region-aware connection model already used for Z.AI without mixing incompatible key types or endpoints.

Impact

Operators can connect the Alibaba service and region that matches their key, use Qwen3.6 Plus as the recommended coding and multimodal model, and add other provider model IDs as needed. Both task runs and control-plane inference honor the selected region, while provider credentials remain on the control plane. Compose shape validation completed; the final Caddy adaptation check was unavailable because this sandbox does not expose /var/run/docker.sock.

[roomote-roomote]

No new code issues found. See task

• packages/types/src/model-provider-config.ts:439: The China option is only applied by the task-run inference gateway. Control-plane calls (routing, titles, and summaries) use resolveEffectiveModelRuntimeEnv and create a raw alibaba/... OpenCode config without a regional base URL, so they still target the global endpoint and reject China-region keys. Propagate the selected Alibaba endpoint to that direct configuration path and cover it with a China-region test.

_{Reviewed 437516a}

[roomote-roomote]

Fixed in 437516a: direct control-plane OpenCode calls now receive the selected Alibaba regional baseURL for Model Studio, Coding Plan, and Token Plan. Added China-key coverage for resolveEffectiveModelRuntimeEnv and direct OpenCode config generation. See task