feat: add eLabFTW Cloudron package (Business-Apps) [#669]

Official-image wrapper of elabftw/elabimg 5.6.12 (tag+digest pinned);
localstorage + mysql + ldap addons; httpPort 443 via DISABLE_HTTPS.
No OIDC upstream -> native LDAP flagged auth-risk. First mysql-addon
and first Business-Apps package; 15/~57. Build verified green under
ukrrs-batch.slice. Docs synced (JOURNAL s15, README, STATUS).

Detail + verification: https://projects.knownelement.com/issues/669#note-3938

Package-Workspace/Business-Apps/elabftw/CHANGELOG.md

@@ -0,0 +1,21 @@
+# Changelog
+
+## 1.0.0 — 2026-09-01
+
+Initial Cloudron package (eLabFTW 5.6.12, ticket
+[#669](https://projects.knownelement.com/issues/669)).
+
+- Official-image wrapper around `elabftw/elabimg:5.6.12` (digest
+  pinned); no additions to the runtime image.
+- `start.sh`: MySQL addon wait loop, `CLOUDRON_MYSQL_*` → `DB_*`
+  mapping, `SITE_URL` from `CLOUDRON_APP_ORIGIN`, plain-HTTP mode
+  (`DISABLE_HTTPS=true`, internal port 443), persistent `SECRET_KEY`
+  under `/app/data`, uploads/exports bound into the localstorage volume.
+- Schema lifecycle via upstream `AUTO_DB_INIT` / `AUTO_DB_UPDATE`
+  (runs after the DB wait in `start.sh`).
+- Auth: no OIDC upstream — `ldap` addon enabled and documented mapping
+  table for the sysconfig LDAP panel (**auth-risk: LDAP**); SAML
+  available for an external IdP.
+- Env knobs: `ELABFTW_TZ`, `ELABFTW_MAX_UPLOAD_SIZE`,
+  `ELABFTW_PHP_MAX_CHILDREN`, `ELABFTW_MAX_PHP_MEMORY`,
+  `ELABFTW_AUTO_DB_INIT`, `ELABFTW_AUTO_DB_UPDATE`.