AxonOS Radar 12.0.1

Four fixes, none of them architectural — the pattern common to all four is
that the code had already moved on and the prose describing it hadn't.

Fixed

• SECURITY.md's Scope and Hardening sections still named scripts/radar.py,
  removed at the 8.0.0 open-core cutover; both now name the files that
  actually do the work today (sync_engine_data.py, validate_payload.py).
• docs/THREAT_MODEL.md's Accepted Risks still described assets/app.js as
  rendering card content via innerHTML from escaped strings. That was true
  once; the codebase has carried zero innerHTML calls (all textContent)
  for several releases. The stale entry is removed rather than corrected in
  place, since the risk it described no longer exists.
• CI's schema validation step checked data/radar.json against
  data/radar.schema.json and stopped there — data/signals.schema.json
  and data/trajectory.schema.json are shipped and advertised in the API
  index, but nothing ever validated live data against either. Both are now
  actually enforced, not just pointed to.
• validate_payload.py's invariant gate was hardcoded to payload versions
  (3, 4). The live payload has been on version 5 for some time, which means
  every v3/v4 invariant — required evidence_tier/inclusion_reason, and
  all four counts.* reconciliation checks — has been silently skipped on
  every run, with no warning and a green check mark throughout. Verified
  directly against live production data before extending the known-version
  set: 120/120 projects still carry both legacy fields, and all four counts
  reconcile, so version 5 is added to the known set rather than exempted from
  checking. Any future unrecognized version now fails the build loudly
  instead of silently skipping the invariants it doesn't know how to check.