Moves SCCACHE_GHA_ENABLED environment variable setup into a conditional step for GitHub-hosted runners in both ci.yml and ui_tests.yml. This ensures the variable is only set when appropriate, improving workflow flexibility.

Added a conditional to only install 'just' with Homebrew when the workflow is running on GitHub-hosted runners in both ci.yml and ui_tests.yml. This prevents unnecessary installation steps on self-hosted or other environments.

Added commented lines for 'runs-on: macos-26' in both ci.yml and ui_tests.yml to document the previous runner configuration while continuing to use self-hosted macOS runners.

The CI workflow now explicitly cleans DerivedData, builds the project, and runs tests without building. Added a new 'test-without-building' recipe to the justfile and updated the workflow to use it, improving build efficiency and clarity.

Consolidated test-all and test-without-building into a single _test action recipe to reduce duplication. Updated test-all and test-without-building to use the new _test action with appropriate arguments.

Replaces the 'build' step in CI with 'build-for-testing' and refactors the justfile to introduce reusable build and test recipes. Adds variables for derived data and build flags, and streamlines test invocation for specific targets. This improves maintainability and flexibility of build and test automation.

Introduces a new XCTest plan file for app unit tests and updates the Xcode project to include it in the resources build phase. This enables more flexible and configurable test execution for the GemTests target.

Removed unused 'xcbeautify' and 'list' recipes for clarity. Added '@' to several commands for consistent output suppression and improved the 'download-wallet-core' recipe to use silent curl.

Sets RUSTC_WRAPPER in the sccache setup step for GitHub-hosted runners instead of globally in ci.yml and ui_tests.yml. This ensures the environment variable is only set when appropriate.

Introduces a new 'test-ui-without-building' Justfile recipe and updates the UI test workflow to use it. This allows running UI tests without rebuilding, improving CI efficiency. Also adds a separate build-for-testing step to the workflow.

Replaces the commented-out 'rm -rf build/DerivedData' step with an active 'just clean' command in the CI workflow for improved consistency and maintainability.