build: add roaming module gradle file, cap local JVM heap

Include feature:roaming/build.gradle.kts (missed from the module commit) and keep the reduced Gradle heap (-Xmx768m) so local light builds don't freeze the 2GB server.

feature/roaming/build.gradle.kts

@@ -0,0 +1,11 @@
+plugins {
+    alias(libs.plugins.convention.featurePlugin)
+}
+
+android {
+    namespace = "com.rtbishop.look4sat.feature.roaming"
+}
+
+dependencies {
+    implementation(project(":core:data"))
+}