feat(date-memories): add DateReflection domain model

app/src/main/java/app/closer/domain/model/DateReflection.kt

@@ -0,0 +1,34 @@
+package app.closer.domain.model
+
+/**
+ * A partner's private post-date reflection (3 prompts). The content is couple-key encrypted and lives in
+ * a read-gated `secure/payload` subdoc — neither partner can read the other's until BOTH have reflected
+ * (enforced by the Firestore rule, mirroring the daily-question reveal). Privacy-native by design.
+ */
+data class DateReflection(
+    val dateId: String = "",
+    val userId: String = "",
+    val favoriteMoment: String = "",
+    val surprise: String = "",
+    val appreciated: String = "",
+    val isRevealed: Boolean = false,
+    val createdAt: Long = 0L,
+    val schemaVersion: Int = SCHEMA_VERSION
+) {
+    val isEmpty: Boolean
+        get() = favoriteMoment.isBlank() && surprise.isBlank() && appreciated.isBlank()
+
+    companion object {
+        const val SCHEMA_VERSION = 1
+    }
+}
+
+/** Per-user reflection progress for a completed date, derived at read time (not stored). */
+enum class DateReflectionState {
+    /** Neither this user has reflected. */
+    NONE,
+    /** This user reflected; waiting on the partner. */
+    AWAITING_PARTNER,
+    /** Both reflected — ready to reveal / revealed. */
+    BOTH_DONE
+}