Add native Kotlin/Compose Android port

Full feature-parity port of the iOS app under ./android (package
app.voltplan.cable): Systems, bottom-nav system detail (Overview,
Components, Batteries, Chargers), calculator/loads, battery & charger
editors, overview with runtime/charge goals, Bill of Materials with PDF
export, VoltPlan PocketBase component library, and Aptabase analytics.
Room persistence, 5-language localization. Verified to build (assembleDebug).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

android/settings.gradle.kts

@@ -0,0 +1,24 @@
+pluginManagement {
+    repositories {
+        google {
+            content {
+                includeGroupByRegex("com\\.android.*")
+                includeGroupByRegex("com\\.google.*")
+                includeGroupByRegex("androidx.*")
+            }
+        }
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+rootProject.name = "Cable"
+include(":app")