* feat(zec2_rotatekeys): rotate/reset server-side secrets without exposing values
New tool for the leaked/overwritten prod .env case: -Rotate KEY regenerates a
key ON THE SERVER (openssl rand -hex 32) so the value never leaves the box;
-Set KEY takes an operator-known value from a masked prompt and streams it over
SSH stdin (never a command arg, never echoed). Backs the server .env up to a
timestamped .bak first, updates keys atomically (match-or-append), auto-detects
backend/.env from deploy.preserve, restarts only with -Restart, and -WhatIf
previews the plan. Docs added to README + CHANGELOG.
* fix(zec2_rotatekeys): recreate container on -Restart so the new .env loads
A plain 'docker compose restart' reuses the container's existing environment
and would NOT pick up env_file changes, leaving the app on the old secrets
after a rotation. -Restart now runs 'up -d --force-recreate <svc>', the
reliable way to apply the new .env. Docs updated to match.
