Version 2.0.0-beta

Replace XCResultKit usage with direct xcresulttool and xccov parsing using local Codable models.
Remove XCResultKit as a package dependency from Package.swift.
Migrate JUnit, summary/test formatting, coverage formatting, and issues JSON paths to the new model/tooling layer.
Keep output compatibility where possible while aligning with modern xcresulttool payloads.
Raise the minimum supported platform to macOS 12.
Keep expected failures as a distinct state in human-readable outputs, while emitting them as passing test cases in JUnit/Sonar XML for compatibility.
Treat unknown --coverage-targets values as an error instead of silently producing empty coverage output.