v0.9.0

Added

• A footprint adapter: tools discovered by the config traces they leave.
  Roots are configuration (footprint.roots in instance.yaml: XDG config,
  data, and state, home dotfiles via dot_only, per-OS conventions via
  os:); the same tool across roots merges into one observation with a
  footprint per trace, and a configured root is never itself a tool. A tool
  whose name matches another adapter's declared entry is attributed to it
  (governed_by, a new general fact the triage honors) instead of listing
  as ungoverned, so discovery only asks about tools with no decision on
  record. Debris never becomes a question: OS artifacts, shell and editor
  state, backup copies, and the cache dir are skipped by name
  (ignore: extends the list, ignore_defaults: false drops it). All of
  it stat-only: nothing is ever opened, so credential-bearing configs
  contribute their name and shape, never their contents; a root the scan
  cannot list refuses loudly into the failed-scan alert, naming itself,
  instead of silently shrinking coverage. Opt-in: no section, no scan.