Add .envrc for Nix environment setup

.envrc

@@ -0,0 +1,14 @@
+# Check if nix is available
+if command -v nix &> /dev/null; then
+    use flake
+    
+    echo "✅ Nix development environment loaded"
+else
+    # Nix is not available - show instructions for non-Nix users
+    echo "⚠️  Nix not detected. Please ensure the following are installed manually:"
+    echo "   - Java JDK 17"
+    echo "   - Python 3 with invoke package"
+    echo "   - Android SDK"
+    echo "   - FVM (Flutter Version Management)"
+    echo "💡 To use Nix: Install from https://nixos.org/download.html"
+fi