Initial bootstrap: cpanel-importer sanitization sandbox

Skeleton for the cpanel-importer Docker container — a one-shot
sandbox the WHP panel invokes BEFORE extracting a customer cpmove
tarball. See cpanel-import-container-spec.md (in /workspace/) for the
full design.

What this ships in v1.0:

- Dockerfile: almalinux:10-minimal + PHP 8.4 (Remi) + ClamAV 1.4 +
  SaneSecurity Foxhole.PHP rules + tar/mariadb-client/rsync. Runs as
  UID 999 (whp-import) via the panel-side --user 999:999 flag.

- scripts/entrypoint.sh: validates env, runs (optional) freshclam,
  drives extract -> scan-files -> scan-dbs -> rsync -> report.json.

- scripts/extract.sh + scripts/lib/scan-symlinks.php: pre-extract
  symlink scan ported standalone from
  web-files/libs/CpanelBackupImporter.php (the existing 2026-05-29
  whp02 destruction-vector fix). Aborts with exit 3 before tar runs
  if any DANGEROUS symlink is found.

- scripts/scan-files.php: ClamAV walk + classify-and-action. v1.0
  ships with an empty cleaner registry — every hit is
  QUARANTINE_ONLY. Cleaner hooks are stubbed for v1.1.

- scripts/scan-dbs.php: regex MyISAM -> InnoDB rewrite (always
  applied), WordPress identification, and ONE WP content scan check
  (siteurl_external_domain). v1.1 will grow the check set.

- scripts/lib/safety-net.php: container-narrow open_basedir
  allow-list, much tighter than the panel-side one.

- .gitea/workflows/build-push.yaml: builds + smoke-tests +
  PHP-syntax-checks + bash-syntax-checks before pushing to
  repo.anhonesthost.net/cloud-hosting-platform/cpanel-importer.

- tests/build-fixtures.sh: builds cpmove-clean.tar.gz (benign WP
  dump) and cpmove-alfa.tar.gz (the ALFA-shell symlink-to-/etc
  vector) for local end-to-end testing.

- README.md / CONTRIBUTING.md: docker-run invocation, bind-mount
  catalog, report.json schema, how to add a cleaner pattern or a WP
  scan signature.

Local acceptance test results:
- clean fixture -> status=completed, 3 MyISAM->InnoDB, no flags, 0
- ALFA fixture -> exit 1, status=failed, failed_stage=extract,
  "tarball contains dangerous symlinks; aborting" on stderr
- compromised-siteurl fixture -> imported_into_new_server=false,
  .flagged file written, summary_for_panel.show_alert=true

Image size: 197 MB compressed (gzipped docker save), ~397 MB unique
layers extracted. Well under the spec's 600 MB compressed / 1.2 GB
extracted budget.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 An Honest Host, LLC / cloud-hosting-platform contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.