tools/analyze_impact library

Core tool for analyzing the impact of upgrading a package to a new version.

Orchestrates all services to:

1. Resolve the current version from the project's pubspec/lockfile.
2. Fetch breaking-change data from multiple sources in parallel.
3. Map breaking changes to actual code locations via AST analysis.
4. Detect cascading dependency conflicts.
5. Compute a risk score and produce a structured AnalysisResult.