Roadmap: does the design hold up to the way the code changes? #65

Goal

codeheat answers one question per area of a repository: does the design hold up to the way the code actually changes? ("design fit"). The report should show, at a glance and for someone who has never seen the repository:

1. where change concentrates (hot territories, weighted towards recent work),
2. whether the structure contains change (change radius, distant coupling, cliques, copy families, erosion),
3. where the design fails and where to start so the codebase scales (ranked entry points with evidence and a design move).

Milestones

• Trustworthy history: recency weighting, mechanical commits, mirrored test pairs, logical changes (Count only the work that matters: recency, mechanical commits, mirrored test pairs, logical changes #57)
• Change radius and propagation cost (Report how far a change spreads: change radius and propagation cost #58)
• Distant coupling, cliques, unstable interfaces, dependency direction (Rank distant coupling, cliques, unstable interfaces and dependency direction #59)
• Copy families (Find copy families that change in lockstep #60)
• Erosion, chronic and acute hotspots, fix density (Show whether the design holds over time: erosion, chronic hotspots, fix density #61)
• Contracts and configuration in the universe (Include contracts and configuration as coupling-only files #62)
• Territories, ranked entry points, report contract v2 (Territories, ranked entry points and report contract v2 #63)
• Report UI around design fit (Report UI around design fit: everything at a glance #64)

Each milestone is validated on several real repositories (open source and private) before it merges. The report contract moves to schemaVersion: 2 once territories and entry points exist.