Add Just Doctor

Create a repository-native just doctor command, execute it against the current local environment, and leave the command covered by focused tests. Treat the dependency inventory as the single source of truth.

1. Read The Repository Contract

Read the applicable agent instructions and setup docs, resolving repository file references from the repository root. Check ./Justfile and then ./justfile; inspect configuration modules, environment examples such as ./.env.example, and test conventions. When a filename varies by repository, start the search at the repository root and record the discovered path in ./relative/path form. Find the canonical local environment file and the repository's existing dotenv loader. In linked worktrees, follow the repository's documented rule for locating the primary worktree environment.

Completion criterion: identify the exact recipe file, runtime/config entrypoint, canonical local environment file, test layer, and validation commands before editing.

2. Build The Dependency Inventory

Trace environment lookups from runtime code, configuration schemas, ./.env.example-style contracts, Compose/Helm manifests, and existing provider clients. For every runtime dependency controlled by environment configuration, record: