Three-part fix for the silent data-loss failure mode that survives DC-039:
If SERVICES_FILE env was unset, platformPaths.dataDir resolved to /etc/dashcaddy
(image-layer path), and audit/license/error logs would silently land there and
vanish on every container recreate.
1. platform-paths.assertSafe({mode:'production'}) — throws FATAL on forbidden
zones (/app/src,routes,scripts,utils,managers,security + /etc/* + /usr + /var).
Bypassed with SKIP_DATA_DIR_GUARD=1.
2. server.js calls assertSafe() before any runtime work.
3. start.sh one-time migration: scans 6 known image-layer zombie paths,
copies non-empty content to bind mount with 'migrated-' prefix,
gated by sentinel file. Survives set -e per-file failures.
19/19 platform-paths tests + 5/5 shell migration tests.
Suite: 1066/1067 (1 pre-existing public-routes-drift failure from in-flight
auth refactor, untouched by this commit).
Verified live on DNS2: live audit log at /app/data/audit-log.json (315KB,
active) is unaffected; vestigial 2-byte /app/src/security/audit-log.json +
140KB /app/src/utils/error.log (pre-DC-039 era) will be recovered on next
container recreate.
