fix: migrate old backend fixes into SPA migration branch

[ZeroPointSix]

Summary

• Migrates the applicable old PR work from fix(verification): 验证码提取保留原文大小写 #103, [codex] add domain claim endpoint #105, and Fix OAuth token save validation scope mismatch #108 into the feat(frontend): Ant Design Pro SPA migration (P0–P5 + review fixes) #109 SPA migration branch.
• Ports the fix(imap): 修复验证码提取详情错配 #67 IMAP ordering/latest-detail behavior into the current service layer and adds regression coverage.
• Adds focused frontend type/lint/test fixes on the feat(frontend): Ant Design Pro SPA migration (P0–P5 + review fixes) #109 branch so the Ant Design Pro checks complete cleanly.
• Defers perf: optimize email fetching with SSE, caching, and concurrent IMAP #36 intentionally: it is a larger SSE/cache/controller rewrite tied to the old frontend surface and should be handled as a separate follow-up after the SPA migration stabilizes.

Validation

• Passed: python -m unittest -v tests.test_verification_extractor tests.test_ai_fallback_trigger_condition tests.test_external_pool tests.test_pool_flow_suite tests.test_oauth_tool tests.test_imap_connection_reuse tests.test_verification_extract_log (173 tests).
• Passed: npm run lint, npm run test (33 tests), and npm run build in ant-design-pro.
• Passed: python -m compileall outlook_web tests.
• Passed: git diff --check.
• Full backend discovery was run with python -m unittest discover -s tests -v; the remaining failures are isolated to tests.test_pool_cf_real_e2e, where the real CF Worker claim call returns HTTP 400 / UPSTREAM_BAD_PAYLOAD. Browser tests were skipped because Playwright/Werkzeug support is unavailable in the environment.

Refs #109, #103, #105, #108, #67, #36.

[ZeroPointSix]

发布线路调整

#112 当前定位调整为：SPA 迁移阶段的后端能力桥接 PR。

新的流程：

• 第一阶段：发布跟踪：旧前端紧急版本（先行发布） #115 旧前端紧急版本，先固定并发布 main。
• 第二阶段：发布跟踪：新前端 SPA 迁移版本（旧前端版本后） #116 SPA 迁移版本，将发布后的 main 同步到 feat(frontend): Ant Design Pro SPA migration (P0–P5 + review fixes) #109，再重新核对 fix: migrate old backend fixes into SPA migration branch #112。

注意事项：

• fix: migrate old backend fixes into SPA migration branch #112 当前包含 fix(verification): 验证码提取保留原文大小写 #103/[codex] add domain claim endpoint #105/Fix OAuth token save validation scope mismatch #108/fix(imap): 修复验证码提取详情错配 #67 的迁移内容，但不要假设所有内容都无需重新核对。
• fix(imap): 修复验证码提取详情错配 #67 的 detail 缺失重取补丁需要在最终 SPA 线确认不丢失。
• perf: optimize email fetching with SSE, caching, and concurrent IMAP #36 保留为独立性能优化，不进入 SPA 首版。

[ZeroPointSix]

仓库清理结论：本 PR 用于把旧后端修复桥接到 SPA 分支。根据 #116 的固定基线记录，#67、#103、#108、#114、#119 等适用修复已进入 main；#109 也已同步该基线并继续独立演进。本 PR 当前与目标分支冲突且已失去独立合并价值，现关闭；若发现 SPA 专属缺口，应基于 #109 当前 head 单独补丁。