Say the whole line, keep the credential out of it, and give Flutter a voice

Three things learned the hard way while chasing a reply chip, all of them
about being able to see anything at all.

The desktop's `FRQ_TRACE` printed the first hundred characters of a line.
Tags come first and a signature is long enough to push every other tag past
that cut, so the truncated form could not answer what a `+reply` said — or
whether there was one — which is the only question the trace exists for. It
prints the line now. Except an `AUTHENTICATE` payload, which is the
credential itself: a trace is something you paste into a bug report, and the
old one wrote a session token into /tmp in the clear.

The Flutter half had no voice at all on a desktop. `print` is
`cljd.core/print` writing to a `*out*` nothing is holding in a compiled
bundle, and `dart:developer` — what `frq.net.dart` uses — goes to the VM
service, not to the process's output, so `just flutter-desktop` shows
neither. The comment there claimed otherwise; it says what is true now, and
what to do instead. Three guesses were spent on that silence before a file
proved the code had been running the whole time.

`frq.debug` is that file, made reusable. `FRQ_JOT` names a path and `jot!`
appends to it; off, it costs a deref. It never throws, because a diagnostic
that takes the app down is worse than no diagnostic, and it appends rather
than truncates, because the interesting run is usually the one after the one
that told you where to look. The wire log goes through it, which is both what
makes the namespace compile — ClojureDart builds what `frq.main` reaches, and
nothing else — and the first thing anyone will want out of it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>