Add media send feature module.

core/models/build.gradle.kts

@@ -16,4 +16,5 @@ android {
 dependencies {
   implementation(libs.kotlinx.serialization.json)
   implementation(libs.jackson.core)
+  implementation(libs.jackson.module.kotlin)
 }

core/models/src/main/java/org/signal/core/models/media/MediaFolder.kt

@@ -6,17 +6,20 @@
 package org.signal.core.models.media
 
 import android.net.Uri
+import android.os.Parcelable
+import kotlinx.parcelize.Parcelize
 
 /**
  * Represents a folder that's shown in a media selector, containing [Media] items.
  */
+@Parcelize
 data class MediaFolder(
   val thumbnailUri: Uri,
   val title: String,
   val itemCount: Int,
   val bucketId: String,
   val folderType: FolderType
-) {
+) : Parcelable {
   enum class FolderType {
     NORMAL, CAMERA
   }

core/models/src/main/java/org/signal/core/models/media/TransformProperties.kt

@@ -9,35 +9,51 @@ import android.os.Parcelable
 import com.fasterxml.jackson.annotation.JsonProperty
 import kotlinx.parcelize.IgnoredOnParcel
 import kotlinx.parcelize.Parcelize
+import kotlinx.serialization.EncodeDefault
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 
 /**
  * Properties that describe transformations to be applied to media before sending.
  */
+@OptIn(ExperimentalSerializationApi::class)
 @Serializable
 @Parcelize
 data class TransformProperties(
+  @EncodeDefault(EncodeDefault.Mode.ALWAYS)
   @JsonProperty("skipTransform")
+  @SerialName("skipTransform")
   @JvmField
   val skipTransform: Boolean = false,
 
+  @EncodeDefault(EncodeDefault.Mode.ALWAYS)
   @JsonProperty("videoTrim")
+  @SerialName("videoTrim")
   @JvmField
   val videoTrim: Boolean = false,
 
+  @EncodeDefault(EncodeDefault.Mode.ALWAYS)
   @JsonProperty("videoTrimStartTimeUs")
+  @SerialName("videoTrimStartTimeUs")
   @JvmField
   val videoTrimStartTimeUs: Long = 0,
 
+  @EncodeDefault(EncodeDefault.Mode.ALWAYS)
   @JsonProperty("videoTrimEndTimeUs")
+  @SerialName("videoTrimEndTimeUs")
   @JvmField
   val videoTrimEndTimeUs: Long = 0,
 
+  @EncodeDefault(EncodeDefault.Mode.ALWAYS)
   @JsonProperty("sentMediaQuality")
+  @SerialName("sentMediaQuality")
   @JvmField
   val sentMediaQuality: Int = DEFAULT_MEDIA_QUALITY,
 
+  @EncodeDefault(EncodeDefault.Mode.ALWAYS)
   @JsonProperty("mp4Faststart")
+  @SerialName("mp4Faststart")
   @JvmField
   val mp4FastStart: Boolean = false
 ) : Parcelable {
@@ -46,7 +62,9 @@ data class TransformProperties(
   }
 
   @IgnoredOnParcel
+  @EncodeDefault(EncodeDefault.Mode.ALWAYS)
   @JsonProperty("videoEdited")
+  @SerialName("videoEdited")
   val videoEdited: Boolean = videoTrim
 
   fun withSkipTransform(): TransformProperties {

core/models/src/test/java/org/signal/core/models/media/TransformPropertiesTest.kt

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.core.models.media
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.module.kotlin.registerKotlinModule
+import kotlinx.serialization.json.Json
+import org.junit.Assert
+import org.junit.Test
+
+class TransformPropertiesTest {
+
+  @Test
+  fun `kotlinx serialize matches legacy json keys`() {
+    val properties = TransformProperties.empty()
+
+    Assert.assertEquals(
+      "{\"skipTransform\":false,\"videoTrim\":false,\"videoTrimStartTimeUs\":0,\"videoTrimEndTimeUs\":0,\"sentMediaQuality\":0,\"mp4Faststart\":false,\"videoEdited\":false}",
+      Json.encodeToString(properties)
+    )
+  }
+
+  @Test
+  fun `kotlinx parse tolerates legacy mp4Faststart key`() {
+    val json = "{\"skipTransform\":false,\"videoTrim\":false,\"videoTrimStartTimeUs\":0,\"videoTrimEndTimeUs\":0,\"videoEdited\":false,\"mp4Faststart\":true}"
+
+    val parsed = Json.decodeFromString<TransformProperties>(json)
+
+    Assert.assertEquals(true, parsed.mp4FastStart)
+    Assert.assertEquals(false, parsed.videoTrim)
+    Assert.assertEquals(false, parsed.videoEdited)
+  }
+
+  @Test
+  fun `jackson serialize matches legacy json keys`() {
+    val properties = TransformProperties.empty()
+
+    val objectMapper = ObjectMapper().registerKotlinModule()
+    val encoded = objectMapper.writeValueAsString(properties)
+
+    Assert.assertEquals(
+      "{\"skipTransform\":false,\"videoTrim\":false,\"videoTrimStartTimeUs\":0,\"videoTrimEndTimeUs\":0,\"sentMediaQuality\":0,\"mp4Faststart\":false,\"videoEdited\":false}",
+      encoded
+    )
+  }
+
+  @Test
+  fun `jackson parse tolerates legacy mp4Faststart key`() {
+    val json = "{\"skipTransform\":false,\"videoTrim\":false,\"videoTrimStartTimeUs\":0,\"videoTrimEndTimeUs\":0,\"videoEdited\":false,\"mp4Faststart\":true}"
+
+    val objectMapper = ObjectMapper().registerKotlinModule()
+    val parsed = objectMapper.readValue(json, TransformProperties::class.java)
+
+    Assert.assertEquals(true, parsed.mp4FastStart)
+    Assert.assertEquals(false, parsed.videoTrim)
+    Assert.assertEquals(false, parsed.videoEdited)
+  }
+}