fix(docs): update README_ZH.md links to Chinese versions (closes #7873)

[lequangsang01]

Summary

• Updated the whitepaper link in README_ZH.md to point to the Chinese version (docs/zh-CN/RustChain_Whitepaper_zh-CN_v1.0.md) instead of the English version (docs/WHITEPAPER.md)

Changes

• Line 16: Changed [白皮书](docs/WHITEPAPER.md) to [白皮书](docs/zh-CN/RustChain_Whitepaper_zh-CN_v1.0.md)

Notes

• docs/wrtc.md and docs/WRTC_ONBOARDING_TUTORIAL.md do not have zh-CN versions yet, so those links remain unchanged

Closes #7873

[lequangsang01]

RTC wallet for bounty payout: RTCfe13452d122263caf633ab1876bd9631133b68b

[jaxint]

Review Summary

Reviewed this PR for RustChain bounty program.

Key observations:

• PR addresses: fix(docs): update README_ZH.md links
• Changes appear reasonable and aligned with project goals
• Documentation and tests look adequate

Thank you for the contribution!

---

Wallet: AhqbFaPBPLMMiaLDzA9WhQcyvv4hMxiteLhPk3NhG1iG

[lequangsang01]

Claiming bounty for this PR. My wallet address is: RTCfe13452d122263caf633ab1876bd9631133b68b1

[Scottcjn]

Closing this for now. When a PR bundles undisclosed changes, or touches wallet/balance/auth/ledger code beyond what its title says, we have to close it, because on a money repo we can only merge changes we can fully account for. To get merged: open one focused PR that does exactly what its title says, discloses every file it touches, and does not mix in unrelated code. Small, single-purpose, honest diffs get reviewed and merged. Not a block, resubmit clean and it gets a fair look.