Hillchart: visualize project progress by analyzing the codebase

When the user types /hillchart and references a project, do the following:

1) Load the project artifacts (required)

• Read the plan at projects/<domain-name>/<project-name>/plan.md
• Read the shaping doc at projects/<domain-name>/<project-name>/shaping.md (if exists)
• Read all task files in projects/<domain-name>/<project-name>/tasks/
• Identify scopes and their expected deliverables
• Check for open PRs related to the project (see step 3a)

2) Extract expected artifacts from the plan

For each scope, extract:

• Models: class names mentioned (e.g., StripePayout, StripePayoutItem)
• Migrations: expected table names
• Jobs: Sidekiq/background job class names