pip: requirements.txt project renders as "root" in the manifest tree

[bomly-guy]

In the grouped manifest tree, every subproject renders a real project name except pip, which renders the literal string root:

  ├─ services/api (subproject, gomod)
  │  └─ acme.example/api — 2 packages [go.mod]
  └─ services/billing (subproject, pip)
     └─ root — 12 packages [requirements.txt]

Repro: bomly scan --recursive (bomly 0.18.0) on a monorepo fixture containing services/billing/requirements.txt (two pinned entries, no lockfile), alongside npm and Go subprojects.

Expected: something meaningful for a requirements.txt project — the subproject directory name (billing) seems like the natural fallback, matching how other detectors name their root when the manifest carries no name.