Initial commit: Conjuga Spanish conjugation app

Includes SwiftData dual-store architecture (local reference + CloudKit user data),
JSON-based data seeding, 20 tense guides, 20 grammar notes, SRS review system,
course vocabulary, and widget support.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Conjuga/SharedModels/Package.swift

@@ -0,0 +1,13 @@
+// swift-tools-version: 6.0
+import PackageDescription
+
+let package = Package(
+    name: "SharedModels",
+    platforms: [.iOS(.v18)],
+    products: [
+        .library(name: "SharedModels", targets: ["SharedModels"]),
+    ],
+    targets: [
+        .target(name: "SharedModels"),
+    ]
+)