- crypto.go: Add runtime validation to Encrypt() that verifies the key file
still exists on disk before encrypting. If the key was deleted while Pulse
is running, encryption now fails with a clear error instead of creating
orphaned data that can never be decrypted.
- hot-dev.sh: Auto-generate encryption key for production data directory
(/etc/pulse) when HOT_DEV_USE_PROD_DATA=true and key is missing. This
prevents startup failures and ensures encrypted data can be created.
- Added test TestEncryptRefusesAfterKeyDeleted to verify the protection works.