feat: LoTW confirmed-grids sync card — fetch confirmed QSO grids directly from ARRL LoTW (lotwreport.adi) and merge with Wavelog grids; credentials stored locally

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/model/Settings.kt

@@ -84,6 +84,13 @@ data class WavelogSettings(
     val isConfigured: Boolean get() = url.isNotBlank() && token.isNotBlank()
 }
 
+data class LoTWSettings(
+    val callsign: String = "",
+    val password: String = ""
+) {
+    val isConfigured: Boolean get() = callsign.isNotBlank() && password.isNotBlank()
+}
+
 data class RadioControlSettings(
     val enabled: Boolean,
     val radioModel: String,

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/ILoTWRepository.kt

@@ -0,0 +1,28 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.repository
+
+/** Fetches confirmed gridsquares directly from ARRL LoTW. */
+interface ILoTWRepository {
+
+    /**
+     * Fetch all confirmed (QSL_RCVD=Y) gridsquares for the given LoTW account.
+     * Returns the 4-char grid set, or null on any failure (network / bad credentials).
+     */
+    suspend fun fetchConfirmedGrids(callsign: String, password: String): Set<String>?
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/IMainContainer.kt

@@ -33,6 +33,7 @@ interface IMainContainer {
     val amSatRepo: IAmSatRepository
     val updateRepo: IUpdateRepository
     val wavelogRepo: IWavelogRepository
+    val lotwRepo: com.rtbishop.look4sat.core.domain.repository.ILoTWRepository
     val radioTrackingService: IRadioTrackingService
     val mutualPassData: StateFlow<MutualPassData>
     fun setMutualPassData(data: MutualPassData)

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/ISettingsRepo.kt

@@ -100,4 +100,9 @@ interface ISettingsRepo {
     fun getWorkedGrids(): Set<String>
     fun setWorkedGrids(grids: Set<String>)
     //endregion
+
+    //region # LoTW confirmed-grids settings
+    val lotwSettings: StateFlow<com.rtbishop.look4sat.core.domain.model.LoTWSettings>
+    fun updateLoTWSettings(settings: com.rtbishop.look4sat.core.domain.model.LoTWSettings)
+    //endregion
 }