research: predeclared Re150 VIV driver and logic (research-only)

viv.py: exact undamped harmonic update under the last completed force,
y = 0 response cycles with eligibility, 10-cycle blocks, settle/score with
deterministic restart, conditional velocity seed, scoring metrics. run.py:
Simulation-API driver (set_body + run(1)), RHS = CME + Wen from the moving
diagnostics, raw CME/obs/node terms logged, fail-closed bounds, caps and
input rejection, outputs outside the checkout. CPU tests for the logic and
the real config loader. Predeclare: stale failure sentence removed.

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

docs/validation/leontini_viv_predeclare.md

@@ -45,8 +45,8 @@ this page is jointly agreed.
   F_last → candidate (y_{n+1}, v_{n+1}) by the update below → `set_body` with
   offset y_{n+1} and wall velocity (y_{n+1} − y_n)/dt with lattice dt = 1 (interval average; a
   different quantity from the endpoint v_{n+1}) → `run(1)` → only on success:
-  commit y_n ← y_{n+1}, v_n ← v_{n+1}, F_last ← force read for that step. Any
-  failure leaves the Simulation failed (existing lifecycle). Whether the
+  commit y_n ← y_{n+1}, v_n ← v_{n+1}, F_last ← force read for that step (failure
+  semantics: see the window section). Whether the
   measured force represents the interval's start, midpoint or end is not
   asserted; the one-step lag is declared, not corrected.
 - Initial state: fluid at rest except the uniform inlet; y_0 = v_0 = 0;