docs: rewrite governance templates into human-readable prose

[Pigbibi]

Summary

Continuation of the QSL sibling-repo documentation de-templating effort (11 repos already merged). This is a pure documentation rewrite — no code, config, or workflow logic changes.

• README.md / README.zh-CN.md: moved the "QSL architecture role" field list to after the "What this repository is" human-readable introduction, so the narrative comes first. Content unchanged, only reordered. Chinese README link and the investment risk disclaimer are untouched.
• CONTRIBUTING.md: removed the auto-generated "## 中文摘要" metadata block (identical boilerplate across all QSL sibling repos, just the repo name swapped in). Folded the relevant repo-specific risk note into Ground Rules as a rule about verifying strategy-promotion/live-enablement changes against documented evidence gates before merging.
• SECURITY.md: removed the same "## 中文摘要" block; all security reporting process content is unchanged.
• CODE_OF_CONDUCT.md: removed the "## 中文摘要" block. Its risk note overlapped with the existing Project Scope section, so merged the repo-specific point (discussions touching strategy promotion / live-enablement / live systems should stay evidence-based) into that section instead of duplicating it.

No other files contained the same template patterns.

Test plan

• git diff --stat reviewed — only the 5 markdown files above changed, no code/config/workflow files touched.
• Manually read each changed file end-to-end to confirm no factual content was dropped, only reordered/de-duplicated.
• N/A automated tests (documentation-only change).

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