Watch settings: clarify load indicator label as 'Load (PWM)'

The shorter 'Load' label was ambiguous — testers reading the dashboard
might not realize the bar tracks the wheel's PWM duty cycle. Adding the
parenthetical keeps the column tight while spelling out what the
indicator measures, mirroring how alarm rules expose the PWM metric.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: eried

app/src/main/res/values/strings.xml

@@ -96,7 +96,7 @@
     <string name="watch_show_wheel_battery">Show wheel battery</string>
     <string name="watch_show_phone_battery">Show phone battery</string>
     <string name="watch_show_watch_battery">Show watch battery</string>
-    <string name="watch_pwm_display">Load indicator</string>
+    <string name="watch_pwm_display">Load (PWM) indicator</string>
     <string name="watch_pwm_bar">Bar</string>
     <string name="watch_pwm_numbers">Numbers</string>
     <string name="watch_pwm_both">Both</string>