feat(zhipu): proxy GLM through an API key account

[caigee-cmd]

Summary

• Add Zhipu GLM as an in-process provider. A pasted API key uses the official OpenAI-compatible endpoint, with pay-as-you-go and Coding Plan as account modes, and Coding Plan quota on the console.
• Rewrite GLM reasoning onto the levels Zhipu accepts: older models use high/max, and glm-5.3 also accepts low.
• Change add-account into a provider picker first. Zhipu then asks only for the account mode and API key, and form fields fill the row.

Test plan

• go test ./...
• Frontend typecheck via tsc -b during npm run sync
• Add a Zhipu account from the console and send zhipu/glm-5.2
• Confirm a Coding Plan key shows the 5-hour and weekly quota windows