Deactivating the plugin deletes all saved settings #36

Problem

Temporarily deactivating Simple Analytics deletes all 18 plugin options, including custom domains and exclusion rules. Reactivating restores defaults rather than the user's configuration.

Reproduction

1. Configure a custom domain and at least one exclusion rule.
2. Deactivate the plugin in WordPress.
3. Reactivate it and inspect its settings.

Actual: saved configuration is gone.
Expected: deactivation preserves configuration; deleting/uninstalling the plugin performs cleanup.

Evidence

Reproduced with plugin 1.109, WordPress 7.1 and PHP 8.4.25 using the installed plugin and WordPress deactivate_plugins() against an isolated temporary options table on the same server: 18 options before, zero afterward. The live plugin was left active.

src/Plugin.php:39 registers onUninstall() as the deactivation callback; that callback deletes every SettingName option.

Acceptance

Preserve settings across deactivation/reactivation and retain deliberate cleanup on uninstall, including appropriate multisite handling.