Rename package and APKs to NilsMG4, credit Fatih, add SPECS.md

- applicationId com.evsuite.abrp -> com.stinnesbeck.nilsmg4 (the car
  build is .unstable); the Java namespace is unchanged. Installs next to
  upstream's app rather than over it.
- APK names NilsMG4-*.apk, debug builds included; build-car follows.
- OTA install-result action, cache/download names, User-Agent and log
  tags follow the new name.
- About credits fatihdonmezdev / FatihsMG4.
- SPECS.md journals what changed and what is still to do, starting
  with pointing the About link and QR code at git.stinnesbeck.com/nils/mg4.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/src/main/java/com/evsuite/abrp/ConsumptionCloudClient.java

@@ -28,7 +28,7 @@ import java.util.List;
  * picks up right where the old one left off instead of showing zeroes.
  */
 final class ConsumptionCloudClient {
-    private static final String TAG = "FatihsMG4.Mongo";
+    private static final String TAG = "NilsMG4.Mongo";
     private static final long CONSUMPTION_SYNC_INTERVAL_MS = 2 * 60_000L;
     private static final long CHARGE_RETRY_INTERVAL_MS = 5 * 60_000L;
     private static final long HISTORY_FETCH_INTERVAL_MS = 5 * 60_000L;

app/src/main/java/com/evsuite/abrp/ConsumptionTracker.java

@@ -216,7 +216,7 @@ final class ConsumptionTracker {
         if (cloudLifetime.km > local.km) {
             lifetime.set(cloudLifetime.km, cloudLifetime.kwh, cloudLifetime.hours, cloudLifetime.soc);
             persist();
-            Log.i("FatihsMG4.Consumption", "Lifetime baseline synced from cloud: "
+            Log.i("NilsMG4.Consumption", "Lifetime baseline synced from cloud: "
                     + cloudLifetime.km + " km (was " + local.km + " km)");
         }
     }