[GH-2867] Translate Stats & Viz API reference to Chinese (Phase 6)

[jiayuasu]

Part of #2867.

Scope

Translate the small Stats and Viz API reference pages.

Files

• `docs/api/stats/sql.md`
• `docs/api/viz/sql.md`
• `docs/api/viz/java-api.md`

Deliverable

A `*.zh.md` sibling for each English file. Function signatures, parameter names, and code samples remain in English; descriptive prose is translated.