pxx 2.4.2

Added

• Content-truthfulness gate (advisory) — a new axis, separate from permission. Scope /
  R-014 governs what the agent may touch; it does not catch a model that stays fully
  in-scope and still reports something false about the code (quoting a comment that isn't
  there, presenting invented code as real). The objective gates (lint/tests/diff-cap) catch
  broken edits, not confident-but-wrong claims. This ships the first increment: deterministic
  quote-grounding (pxx/truthfulness.py). Every non-trivial code span the model quotes in its
  final narration must appear in content it actually read or wrote — the union of read
  tool-results and edit-tool args accumulated across the run. Grounding is checked
  per-source (a quote must sit inside a single source, so it can't be assembled from two
  unrelated reads) and only edit-tool args count as "written" (a non-edit tool arg is
  model-supplied, not read content, so it can't launder a fabricated quote). Fenced blocks are
  checked line-by-line (a model that quotes a function but elides its docstring is being
  terse, not fabricating; a single invented line is what flags), tolerating spaced info strings
  and CRLF; inline spans are checked only when they look like code (whitespace-normalized, no
  model, fully deterministic).
• Wired into the native loop's COMPLETED path as an advisory, non-blocking, fail-safe check:
  an ungrounded quote emits a metadata-only content_truthfulness event (count + a kind
  breakdown, never the quoted code — the audit stream carries no file contents) plus a
  warning log, but never changes a run's outcome — the try/except swallows any checker
  error so an advisory can't break a run. Advisory-first is deliberate: the false-positive rate
  is measured on real runs (like the reviewer's calibration) before the gate is ever
  promotable to a heal trigger. Prove-before-you-call-it.
• Negative control (shipped in the tests): a fabricated quote MUST flag and a real quote
  MUST pass — a check that cannot go red is not a check. content_truthfulness registered in
  the EVENT_KINDS allowlist.