VDB-9: Add concise Glossary page for Venus core terms

[trumpgpt-bot]

What changed

• getting-started/glossary.md (new) — Glossary page with an H1, a brief intro, and 10 terms as ## sub-headings, each defined in 1–2 sentences consistent with existing docs:
  vToken, Comptroller, Core Pool, Isolated Pools, Collateral Factor, Liquidation, Supply APY / Borrow APY, XVS, VAI, Venus Prime.
  • Internal cross-links to existing pages where natural: Isolated Pools → ../whats-new/isolated-pools.md, Liquidation → ../guides/market-interaction/liquidation.md, XVS → ../tokens/xvs.md, VAI → ../tokens/vai.md, Venus Prime → ../whats-new/prime-yield.md, plus in-page anchors for Core Pool/VAI.
• SUMMARY.md — added * [Glossary](getting-started/glossary.md) directly under "Getting Started", after the FAQ bullet.

Verification

• All cross-link targets confirmed to exist on disk before linking (no broken links).
• Ran the repo's remark lint (npx remark getting-started/glossary.md SUMMARY.md -f) after yarn install — both files: "no issues found". This is the repo's only check (it has format/format:check remark scripts, no test suite).
• Style matched against the existing getting-started/faq.md and SUMMARY conventions (* bullets, space list-item indent).

Risks

• Documentation-only change; no code or on-chain impact. Definitions are descriptive summaries intended for new users, not normative parameter specs.

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Opened by the Venus dev bot. Review required; the bot cannot merge.