research: VIV driver — bounded --smoke --steps N (<=64) --D plumbing mode replaces --max-steps

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/validation/leontini_viv_predeclare.md

@@ -131,6 +131,14 @@ counted from the measured signal; T_n is used only for the seed check.
   only at a few predeclared snapshots. No runtime claim: there is no measured
   timing on this grid yet (the D40/60D receipt is a different, sampled case).
 
+## Plumbing smoke (not the benchmark)
+
+`run.py --smoke --D 20 --steps 32` runs exactly 32 steps of the same BC
+package and coupling loop (no seed, settle or score; never scored);
+status `smoke_ok` iff every step is finite, no_donor stays 0 and the body
+stays inside its box. The physical case is only the default invocation
+(`--D 40`, no `--smoke`).
+
 ## Queued, not in this stage
 
 Leontini et al. JFS 22 (2006) Re = 200, m* = 10, zeta = 0.01, U* = 5.0 (needs