perf(auth): 将 API Key 校验缓存 TTL 延长至五分钟

[g1331]

Summary

将 API_KEY_VERIFY_CACHE_TTL_MS 从 120000 毫秒调整为 5 分钟（300000 毫秒），提高重复 API Key 校验的缓存命中窗口。

Related Issue

无关联 Issue。

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactoring (code improvement without changing functionality)
• Tests (adding or updating tests)
• Build/CI (changes to build system or CI configuration)

Changes

• 将 API_KEY_VERIFY_CACHE_TTL_MS 设置为 5 * 60 * 1000。
• 更新 TTL 边界测试：299999 毫秒内命中缓存，300000 毫秒后重新执行 bcrypt。
• 同步 request-lifecycle.md 中的缓存 TTL 说明。
• 缓存容量与数据库权威鉴权检查保持不变。

Test Plan

• Local tests pass (pnpm test:run)
• Type check passes (pnpm exec tsc --noEmit)
• Lint passes (pnpm lint)
• Manual testing completed（纯后端缓存参数变更，不适用）

已验证：聚焦鉴权测试 30 passed；全量测试 245 files、3646 passed、1 skipped；format:check、production build 与 pre-commit hooks 均通过。构建仅有已知的 Turbopack NFT tracing warning。

Checklist

• Code follows the project's coding standards
• Tests have been added where necessary
• Documentation has been updated (if applicable)
• Changes do not introduce security vulnerabilities
• Commit messages follow conventions

Screenshots

不适用。

Additional Notes

本 PR 仅包含 TTL、对应边界测试和架构文档三项变更。工作区中原有的落地页未提交改动未包含在本 PR 中。

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.54%. Comparing base (89878d7) to head (7616131).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #291   +/-   ##
=======================================
  Coverage   72.54%   72.54%           
=======================================
  Files         245      245           
  Lines       14519    14519           
  Branches     4837     4837           
=======================================
  Hits        10533    10533           
  Misses       2600     2600           
  Partials     1386     1386           

Flag	Coverage Δ
verify	72.54% <100.00%> (ø)

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