feat(sanitize): in-place, length-preserving log de-identification

Adds internal/sanitize: rewrites the customer-identifying spans that
internal/privacy detects (domain/FQDN/e-mail/AD/public-IP/timezone) with
same-length neutral fillers, in place, without changing the file format.

- Fillers keep byte length: "sigma.sbrf.ru" -> "xxxxx.xxxx.xx", IP ->
  "00.000.000.00", "Europe/Moscow" -> "Etc/Universal" (same-length valid
  neutral IANA zone), offset "180" -> "000". Timestamps are not recomputed.
- Lossless recursive archive walk (tar/.sds/gz/tgz/zip): entry names, modes,
  and all embedded timestamps preserved; untouched zip entries copied raw;
  member payload length unchanged so tar headers stay byte-identical; only the
  .gz/.zip compression layer is rebuilt. 0 redactions -> byte-identical output.
- privacy.FindSpans is the one matcher shared by detection and redaction;
  fillers are recognised by isRedactionFiller so a re-scan / second pass is a
  no-op. New privacy FPs fixed along the way: syslog selectors (local7.info),
  "MEVersion" firmware quads, *.conf_bak vendor templates, bundled viewer
  domains.
- Binary members (FRU.bin, localtime, redis-dump.rdb, SOL captures) and
  unreadable nested archives are reported in Result.SkippedBinary, never edited.
- Surfaces: POST /api/sanitize (+ GET /api/sanitize/download), the "Обезличить
  и скачать копию" button in the Customer-data panel, and
  logpile -sanitize <file> (restores mtime/atime).

Verified: re-parsing a sanitized Dell TSR / xFusion / Inspur onekeylog / H3C
.sds yields the identical hardware inventory; re-scan is clean. ADL-067,
bible-local/docs/log-sanitization.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

bible-local/docs/privacy-scan.md

@@ -108,6 +108,13 @@ Reference data, not vendor-detection logic: RFC 2606/5737 names, `pool.ntp.org`
 `foobar.edu` / `issue.net` (stock `hosts.allow` / sshd banner), and factory
 default values (`Asia/Shanghai`, `To Be Filled By O.E.M.`, `NULL`, `0.0.0.0`).
 
+## Redaction
+
+`privacy.FindSpans(line, certFile)` is the matcher shared with
+`internal/sanitize`, which rewrites the same spans in place with same-length
+neutral fillers (see `log-sanitization.md`). The fillers are recognised by
+`isRedactionFiller` so a scan of a sanitized file is clean.
+
 ## Customer guess (`customer.go`)
 
 Findings in `domain`, `resolv`, `ad_ldap`, `cert`, `nsupdate`,