xcode-build-benchmark

# Xcode Build Benchmark Use this skill to produce a repeatable Xcode build baseline before anyone tries to optimize build times. ## Core Rules - Measure before recommending changes. - Capture clean and incremental builds separately. - Keep the command, destination, configuration, scheme, and warm-up rules consistent across runs. - Write a timestamped JSON artifact to `.build-benchmark/`. - Do not change project files as part of benchmarking. ## Inputs To Collect Confirm or infer: - workspace or project path - scheme - configuration - destination - whether the user wants simulator or device numbers - whether a custom `DerivedData` path is needed If the project has both clean-build and incremental-build pain, benchmark both. That is the default. ## Worktree Considerations When benchmarking inside a git worktree, SPM packages with `exclude:` paths that reference gitignored directories (e.g., `__Snapshots__`) will cause `xcodebuild -resolvePackageDependencies` to crash. Create those missing directories before running any builds. ## Default Workflow 1. Normalize the build command and note every flag that affects caching or module reuse. 2. Run one warm-up build if needed to validate that the command succeeds. 3. Run 3 clean builds. 4. If `COMPILATION_CACHE_ENABLE_CACHING = YES` is detected, run 3 cached clean builds. These measure clean build time with a warm compilation cache -- the realistic scenario for branch switching, pulling changes, or Clean Build Folder. The sc...