v4.19.0 — stop inventing a missing wrapper, align the injected policy

Fixed

• The SessionStart stale-wrapper notice no longer invents missing commands.
  policy-inject.mjs still compares ~/.config/cli-dispatch/.installed-version against the
  newest cached plugin version, but it now probes PATH for the backend-agnostic wrapper
  binaries before saying anything is missing. If all core wrappers are present, the notice
  says the installed wrappers are stale and recommends /cli-dispatch:setup without naming
  cli-dispatch-run as absent. If any core wrapper is truly absent, the notice lists the
  missing binary names explicitly and says they are missing from PATH. Backend-specific
  wrappers (ds-agent/cx-agent/ag-agent/oc-agent/cp-agent) are deliberately not probed,
  because a user may have installed only one backend.

• The injected delegation policy now matches the global CLAUDE.md routing rule.
  The first policy sentence no longer narrows runner use to "mechanical work"; it names
  auditability as the binding constraint and allows exploratory work when there is a
  machine-checkable verify command and behavior-changing decisions remain in the
  orchestrator's brief. The /cli-dispatch:run ... --verify guidance, zero-babysitter-token
  emphasis, trivial-inline exception, escalation paragraph, and issue reminder behavior are
  unchanged.