v1.0.0

Initial release.

• DbSettingsProvider: DB-backed WritableSettingsProvider + SettingsInspector
  with a SettingsProvider fallback (config values). Implements describe()
  and describeAll().
• At-rest encryption of secret settings via libsodium (XChaCha20-Poly1305),
  AAD-bound to the setting key: Crypto\KeyRing, Crypto\SodiumCipher,
  key rotation + reencryptSecrets().
• readonly definitions: set()/remove() throw ReadonlySettingException;
  describe() reports isWritable: false.
• Yii3 config-plugin wiring (config/di.php, config/params.php): binds
  WritableSettingsProvider, SettingsProvider and SettingsInspector to the
  same instance; builds KeyRing + SodiumCipher from
  rasuvaeff/yii3-settings-db.cipher (key_id, key) — turnkey encryption.
• Shipped migration for the settings table; SettingRowMapper for typed
  row (de)serialization.
• Requires rasuvaeff/yii3-settings ^1.0.