debian: changelog entry 1.15.2+etm7 for the SunSpec meter sign and battery presence fixes

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

debian/changelog

@@ -1,3 +1,26 @@
+etm-powersync-plugins-modbus (1.15.2+etm7) trixie; urgency=medium
+
+  * sunspec: correct the grid meter sign on Fronius. onMeterBlockUpdated()
+    negated the power of every meter model regardless of vendor, but the
+    Fronius Smart Meter already reports in the nymea convention, where a
+    negative value is feed-in. The negation is now undone for meters sitting
+    under a froniusConnection and only for those; generic and solarEdge keep
+    their previous behaviour. Established on a Primo GEN24 3.0, whose single
+    phase inverter gives the direction reference: the plugin reported the
+    inverter's own phase as importing while the two phases carrying no source
+    read as exporting. The arbiter concluded "insufficient surplus" and left
+    the water heater and the heat pump off while the site was exporting.
+    The energy counters were already correct and are left alone.
+  * sunspec: stop creating a phantom battery on Fronius. A hybrid GEN24
+    publishes model 124 whether or not a battery is wired to it, so a storage
+    child was created unconditionally and sat on batteryCritical forever. The
+    child is now created only when a physical quantity says a battery is
+    there. The state of charge is deliberately not used: 0% cannot be told
+    apart from a real but empty battery. See sunspec/DIVERGENCES.md D-6, the
+    battery-present side is still inferred.
+
+ -- Patrick Schurig <patrick@etm-schurig.eu>  Wed, 05 Aug 2026 15:58:00 +0200
+
 etm-powersync-plugins-modbus (1.15.2+etm6) trixie; urgency=medium
 
   * sunspec: package the vendored SunSpec plugin as nymea-plugin-sunspec-etm01.