feat(admin): add IP whitelist (strict allowlist mode) (#920) (#971)

* feat(admin): add IP whitelist (strict allowlist mode) (#920)

- Add enableWhitelist/whitelist fields to IpBlacklistSettings
- Implement three-layer access control: whitelist → blacklist → daily limit
- Whitelist uses exact match for IPv4/IPv6, regex for patterns
- Whitelisted IPs skip blacklist checks (trusted)
- Fail-closed when cf-connecting-ip missing under whitelist mode
- Frontend: independent whitelist toggle + empty list protection
- Backend: backward compatible (old frontends get defaults)
- E2E tests: config validation + runtime behavior
- Docs: CHANGELOG zh/en updated

Closes #920

* fix(admin): address PR review feedback on IP whitelist

- Add IPv4-mapped IPv6 (::ffff:x.x.x.x) exact match in isWhitelisted
- Include error.message in whitelist regex parse failure log
- Include actual/max size in whitelist size limit error message

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(admin): validate whitelist regex on save and preserve existing whitelist on partial update

- Reject invalid regex patterns in whitelist at save time to prevent runtime lockout
- Preserve existing enableWhitelist/whitelist from DB when older clients omit these fields

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(admin): revert P2 - keep simple ?? defaults for backward compat

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(admin): validate whitelist elements are strings before trimming

Prevents 500 error when whitelist contains non-string elements (e.g. numbers, null)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs(admin): add IP blacklist/whitelist documentation (zh + en)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(admin): fix fingerprint blacklist bypass when cf-connecting-ip absent, improve e2e tests

- Split checkBlacklist into checkFingerprintBlacklist (IP-independent) and checkIpAsnBlacklist
- Fingerprint check now runs before the !reqIp early-return to prevent bypass
- Add afterEach reset to config test group, extract RESET_SETTINGS constant
- Strengthen whitelist-blocks test to deterministic 403 assertion
- Add e2e tests: invalid regex rejection, non-string element rejection, fingerprint-blocks-without-IP

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(admin): suppress no-useless-escape lint warning in whitelist regex check

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

CHANGELOG_EN.md

@@ -10,6 +10,8 @@
 
 ### Features
 
+- feat: |Admin| Add **IP Whitelist (strict mode)** to IP blacklist settings: when enabled, ONLY whitelisted IPs can access rate-limited APIs (create address, send mail, external send mail, user register, verify code); all other IPs are denied (#920)
+
 ### Bug Fixes
 
 - fix: |Admin| Fix `D1_ERROR: LIKE or GLOB pattern too complex` on `/admin/address` and `/admin/users` when searching by full email address (query length pushes the LIKE pattern over D1's 50-byte limit). Long queries now fall back to `instr()` to bypass the LIKE pattern length cap (#956)