feat: add support for C++ interoperability mode in Swift packages

AGENT.md

@@ -0,0 +1,55 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Architecture
+
+XcodeGraph is a Swift Package containing data structures and utilities for modeling Xcode project graphs. It consists of three main modules:
+
+- **XcodeGraph**: Core data structures (Graph, Target, Project, Workspace, etc.) for modeling Xcode projects
+- **XcodeMetadata**: Metadata extraction from precompiled binaries (frameworks, libraries, XCFrameworks)
+- **XcodeGraphMapper**: Maps actual `.xcworkspace`/`.xcodeproj` files to XcodeGraph structures using XcodeProj
+
+### Key Components
+
+- `Sources/XcodeGraph/Models/`: Core data structures like Project, Target, Scheme, BuildConfiguration
+- `Sources/XcodeGraph/Graph/`: Graph representation with dependencies and relationships
+- `Sources/XcodeGraphMapper/Mappers/`: Conversion logic from XcodeProj to XcodeGraph models
+- `Sources/XcodeMetadata/Providers/`: Binary metadata extraction for frameworks and libraries
+
+## Development Commands
+
+### Building
+```bash
+swift build                          # Debug build
+swift build --configuration release  # Release build
+```
+
+### Testing
+```bash
+swift test                                                    # Run all tests
+swift test --skip XcodeGraphMapperTests --skip XcodeMetadataTests  # Linux (no Xcode utilities)
+```
+
+### Linting
+```bash
+mise run lint      # Run SwiftLint and SwiftFormat
+mise run lint-fix  # Auto-fix linting issues
+```
+
+### Documentation
+```bash
+mise run docs:build  # Build documentation
+```
+
+## Platform Support
+
+- Requires macOS 13+ for full functionality
+- Linux support available with limited testing (XcodeGraphMapperTests and XcodeMetadataTests require Xcode utilities)
+- Swift 6.0.3+ with StrictConcurrency enabled
+
+## Testing Strategy
+
+- Unit tests for each module in corresponding `Tests/` directories
+- Test data and mocks in `Tests/*/TestData/` and `Tests/*/Mocks/`
+- XCFramework fixtures in `Tests/Fixtures/` for metadata testing

CLAUDE.md

@@ -0,0 +1 @@
+AGENT.md

Sources/XcodeGraph/PackageInfo.swift

@@ -448,6 +448,7 @@ extension PackageInfo.Target {
             case unsafeFlags
             case enableUpcomingFeature
             case enableExperimentalFeature
+            case interoperabilityMode
         }
 
         /// An individual build setting.
@@ -497,6 +498,7 @@ extension PackageInfo.Target {
                 case unsafeFlags([String])
                 case enableUpcomingFeature(String)
                 case enableExperimentalFeature(String)
+                case interoperabilityMode(String)
             }
 
             public init(from decoder: Decoder) throws {
@@ -506,6 +508,9 @@ extension PackageInfo.Target {
                 condition = try container.decodeIfPresent(PackageInfo.PackageConditionDescription.self, forKey: .condition)
                 if let kind = try? container.decode(Kind.self, forKey: .kind) {
                     switch kind {
+                    case let .interoperabilityMode(mode):
+                        name = .interoperabilityMode
+                        value = [mode]
                     case let .headerSearchPath(value):
                         name = .headerSearchPath
                         self.value = [value]
@@ -543,6 +548,8 @@ extension PackageInfo.Target {
                 try container.encode(tool, forKey: .tool)
                 try container.encodeIfPresent(condition, forKey: .condition)
                 switch name {
+                case .interoperabilityMode:
+                    try container.encode(Kind.interoperabilityMode(value.first!), forKey: .kind)
                 case .headerSearchPath:
                     try container.encode(Kind.headerSearchPath(value.first!), forKey: .kind)
                 case .define: