refactor: migrate core UI and features to KMP, adopt Navigation 3 (#4750)

Signed-off-by: James Rich <2199651+jamesarich@users.noreply.github.com>

core/common/src/androidMain/kotlin/org/meshtastic/core/common/util/Base64Factory.android.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2025-2026 Meshtastic LLC
+ *
+ * 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 org.meshtastic.core.common.util
+
+import android.util.Base64
+
+actual object Base64Factory {
+    actual fun encode(data: ByteArray): String = Base64.encodeToString(data, Base64.NO_WRAP)
+
+    actual fun decode(data: String): ByteArray = Base64.decode(data, Base64.NO_WRAP)
+}

core/common/src/androidMain/kotlin/org/meshtastic/core/common/util/DateFormatter.android.kt

@@ -45,4 +45,16 @@ actual object DateFormatter {
             DateFormat.getDateInstance(DateFormat.SHORT).format(timestampMillis)
         }
     }
+
+    actual fun formatTime(timestampMillis: Long): String =
+        DateFormat.getTimeInstance(DateFormat.SHORT).format(timestampMillis)
+
+    actual fun formatTimeWithSeconds(timestampMillis: Long): String =
+        DateFormat.getTimeInstance(DateFormat.MEDIUM).format(timestampMillis)
+
+    actual fun formatDate(timestampMillis: Long): String =
+        DateFormat.getDateInstance(DateFormat.SHORT).format(timestampMillis)
+
+    actual fun formatDateTimeShort(timestampMillis: Long): String =
+        DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.MEDIUM).format(timestampMillis)
 }

core/common/src/androidMain/kotlin/org/meshtastic/core/common/util/NumberFormatter.android.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025-2026 Meshtastic LLC
+ *
+ * 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 org.meshtastic.core.common.util
+
+import java.util.Locale
+
+actual object NumberFormatter {
+    actual fun format(value: Double, decimalPlaces: Int): String =
+        String.format(Locale.ROOT, "%.${decimalPlaces}f", value)
+
+    actual fun format(value: Float, decimalPlaces: Int): String =
+        String.format(Locale.ROOT, "%.${decimalPlaces}f", value)
+}

core/common/src/androidMain/kotlin/org/meshtastic/core/common/util/UrlUtils.android.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025-2026 Meshtastic LLC
+ *
+ * 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 org.meshtastic.core.common.util
+
+import java.net.URLEncoder
+
+actual object UrlUtils {
+    actual fun encode(value: String): String = URLEncoder.encode(value, "UTF-8")
+}

core/common/src/commonMain/kotlin/org/meshtastic/core/common/util/Base64Factory.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2025-2026 Meshtastic LLC
+ *
+ * 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 org.meshtastic.core.common.util
+
+/** Platform-agnostic Base64 utility. */
+expect object Base64Factory {
+    fun encode(data: ByteArray): String
+
+    fun decode(data: String): ByteArray
+}

core/common/src/commonMain/kotlin/org/meshtastic/core/common/util/DateFormatter.kt

@@ -30,4 +30,16 @@ expect object DateFormatter {
      * Typically shows time if within the last 24 hours, otherwise the date.
      */
     fun formatShortDate(timestampMillis: Long): String
+
+    /** Formats a timestamp into a localized time string (HH:mm). */
+    fun formatTime(timestampMillis: Long): String
+
+    /** Formats a timestamp into a localized time string with seconds (HH:mm:ss). */
+    fun formatTimeWithSeconds(timestampMillis: Long): String
+
+    /** Formats a timestamp into a localized date string. */
+    fun formatDate(timestampMillis: Long): String
+
+    /** Formats a timestamp into a localized short date and medium time string. */
+    fun formatDateTimeShort(timestampMillis: Long): String
 }

core/common/src/commonMain/kotlin/org/meshtastic/core/common/util/NumberFormatter.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2025-2026 Meshtastic LLC
+ *
+ * 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 org.meshtastic.core.common.util
+
+/** Platform-agnostic number formatting utility. */
+expect object NumberFormatter {
+    /** Formats a double value with the specified number of decimal places. */
+    fun format(value: Double, decimalPlaces: Int): String
+
+    /** Formats a float value with the specified number of decimal places. */
+    fun format(value: Float, decimalPlaces: Int): String
+}

core/common/src/commonMain/kotlin/org/meshtastic/core/common/util/UrlUtils.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2025-2026 Meshtastic LLC
+ *
+ * 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 org.meshtastic.core.common.util
+
+/** Platform-agnostic URL encoding utility. */
+expect object UrlUtils {
+    fun encode(value: String): String
+}