fix: support secret key balance usage

[RyanLee-Dev]

Summary

• route sk-api- secret keys to /account/query_balance instead of Token Plan remains
• keep Token Plan keys rendering the existing quota progress bars
• add balance text rendering for secret-key usage surfaces
• update region detection, login validation, auth status, and quota show tests

Validation

• bun run lint (passes with existing warnings in test/sdk/speech.test.ts and test/sdk/video.test.ts)
• bun test test/client/endpoints.test.ts test/auth/timeout-fix.test.ts test/commands/auth/login.test.ts test/commands/quota/show.test.ts test/commands/auth/status.test.ts
• bun run typecheck
• bun run build

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