docs: document auto-time NTP synchronization setting

docs/src/SUMMARY.md

@@ -16,6 +16,7 @@
     - [Dictionaries](ui/settings/dictionaries.md)
 - [Library](library/index.md)
   - [Importing](library/importing.md)
+- [Automatic Time Syncing](time-sync.md)
 - [Troubleshooting](troubleshooting/index.md)
 
 ---

docs/src/settings/index.md

@@ -49,6 +49,16 @@ Automatically enter shared mode when connected to a computer, skipping the
 auto-share = false
 ```
 
+### `auto-time`
+
+✏️
+
+Automatically synchronize the device time via NTP when WiFi connects. This will also set the correct timezone. Uses time.cloudflare.com and ipapi.co.
+
+```toml
+auto-time = false
+```
+
 ### `auto-suspend`
 
 ✏️

docs/src/time-sync.md

@@ -0,0 +1,44 @@
+# Automatic Time Syncing
+
+Cadmus can keep your Kobo's clock accurate by syncing it automatically whenever
+WiFi connects.
+
+## How it works
+
+When enabled, Cadmus will:
+
+1. Detect your timezone based on your IP address.
+2. Fetch the current time from an internet time server.
+3. Update the system clock and hardware clock on your Kobo.
+
+After syncing, the clock in the status bar updates immediately.
+
+## Enabling automatic sync
+
+Open **Main Menu → Settings → General** and turn on **Auto Time**.
+
+You can also enable it manually in your settings file:
+
+```toml
+auto-time = true
+```
+
+## Manual sync
+
+You can trigger a one-time sync without enabling the automatic option:
+
+1. Tap the clock in the top bar.
+2. Select **Sync Time**.
+
+If the sync fails (for example, WiFi is not connected), a notification will let
+you know.
+
+## Privacy
+
+> [!NOTE]
+> Time syncing sends a request to `ipapi.co` to determine your timezone based
+> on your IP address. No personal data is sent — only your device's public IP
+> address is visible to that service as part of the network request.
+
+The actual time is fetched from `time.cloudflare.com` using the standard NTP
+protocol.