Each target group's relationship to the check types that reference it was
previously invisible without cross-referencing /check-types by hand.
handleTargetsPage/renderTargetsTable now resolve that server-side via
loadTargetsPage (group -> referencing check types, enabled or not) and
render it as a status pill per group, plus a stats row (group count,
total targets, check types using them, unused groups) kept live via an
out-of-band swap on every create/update/delete.
Also auto-sizes the targets textarea as you type (targets.html), and
lets the stat-card grid collapse to however many state cards actually
exist instead of leaving empty background where a fixed repeat(6, ...)
had no card to fill.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>