App 2.19.7: meter AC charging too, while the app runs

A session runs whenever power flows into the pack, AC or DC; gaps the
head unit slept through are dropped as before. Dashboard and server
texts no longer say DC only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LhzAVaUyqcw5PkGjz4mWW6

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

@@ -259,7 +259,7 @@
     <string name="price_saved">Charging price saved</string>
     <string name="price_invalid">Enter a valid €/kWh value</string>
     <string name="charge_dc">DC fast charging</string>
-    <string name="charge_ac_not_metered">AC charging (not metered)</string>
+    <string name="charge_ac">AC charging</string>
     <string name="charge_last">Last charge</string>
     <string name="consumption_no_records">No records for this date</string>
     <string name="consumption_day_summary">Distance     %1$.1f km\nEnergy       %2$.2f kWh\nAverage      %3$s\nDuration     %4$d h %5$02d min\nSOC change   %6$.1f %%</string>