The payoff: a hand-authored blueprint's declared taps become recorded output
from one `aura run`. run_signal_r binds each tap (hoisted into flat.taps after
wrap_r nests the signal) to a fresh Recorder before bootstrap, drains the
series after the run, and persists each as a ColumnarTrace via the existing
env.trace_store() — the same trace surface the campaign path feeds, so the
existing chart tooling reads them. Duplicate tap names are refused (the
caller-owned DuplicateBind dedup) before anything persists. A tap-free run
writes no trace store — byte-identical to today. Sweep/reduce leaves taps
unbound (run_blueprint_member untouched). Covered end-to-end: a persisted tap
series, the tap-free no-write guard, and the duplicate-name refusal.
refs #282
