test: add bounded dense-root Jet CV temporal diagnostics

docs/validation/jet_circle_cv.md

@@ -113,3 +113,33 @@ These criteria are fixed before the continuation runs. There is no new physical
 Actual earlier scale-1 pilot cost was 52.3884s launch-to-exit, 46.1414s after READY for800 steps with full-field diagnostics every base step. A naive same-diagnostic3200-step scale-1 extrapolation is about210s; the new876 field samples reduce transfer count but add ray diagnostics and compression. Use conservative planning envelopes210–500s for scale1 and900–3200s for scale2, not timing guarantees. The scale2 conservative envelope accounts for4x cells and4x root steps; sparse sampling mitigates but does not eliminate that cost. Post-READY safety caps are1200s and5400s respectively, replacing the unsuitable fixed1800s assumption. Root owns compilation/startup timeout and serial launch decisions.
 
 Device-envelope estimates remain128/512MiB for s1/s2, at least1GiB free (or twice estimate). Output estimate is under64MiB per run including five primitive snapshots and876 sample records; no all-time populations are saved. Plan/metadata and sampled files are rewritten at each100-reference-time window to retain bounded partial evidence if interrupted. READY still follows compiled warmup and state/time reset, before measured stepping begins.
+
+## Dense-root temporal diagnostic: preparation only
+
+The audited continuation did not resolve time quadrature: all48 audited stride2 RMS changes exceeded their stride1 CV residuals, by factors1.55–11.46. That historical failure and its gates remain unchanged. The following is a measurement-only experiment to test this explanation, not a solver fix, a physics pass, or permission to extend GPU work. The separate periodic global stock-minus-raw mass residual also persists; denser contour quadrature cannot by itself resolve it.
+
+Future launch, only after the computer is online and root approves a serialized bounded run:
+
+```sh
+CUDA_VISIBLE_DEVICES="$VERIFIED_IDLE_GPU" python tests/validation/run_jet_circle_cv.py --repo "$PWD" --output "$NEW_DENSE_S1" --dense-root --steps 800 --scale 1
+CUDA_VISIBLE_DEVICES="$VERIFIED_IDLE_GPU" python tests/validation/run_jet_circle_cv.py --repo "$PWD" --output "$NEW_DENSE_S2" --dense-root --steps 800 --scale 2
+python tests/validation/analyze_jet_cv_continuation.py "$NEW_DENSE_S1" "$NEW_DENSE_S2" --output "$DENSE_COMPARISON_JSON"
+```
+
+This mode fixes Re100,beta.1 and reference t=0..800 (t*≈.9965), with800/3200 root intervals and801/3201 endpoint records. It is mutually exclusive with --continuation and rejects longer runs or other scales/Re. Physical geometry, source manifest, solver, velocity commands, kernel and raw observation path are unchanged. There are no new finest-hop hooks. Existing GPU population downloads occur every root interval for CPU primitive diagnostics; those distributions are discarded rather than retained.
+
+Dense scalar records contain CV endpoint inventories, each flux and split momentum terms, density/speed, physical composite mass, exact cumulative raw partitions and cumulative absolute aperture net mass. Rays remain on the exact old reference cadence:0..100 at dt1, then104..800 at dt4,276 samples for each scale. Schema2 maps their smaller arrays through ray_sample_indices into the dense records. Full primitive snapshots occur only at reference0,100,800. Saved data is capped at32MiB per case; dense arrays are scalar diagnostics, not all-time full fields. Schema/unit metadata, file hashes, complete-schedule checks and matched root time intervals remain mandatory.
+
+The analyzer derives root strides1,2,4 and the exact old cadence from the SAME dense primitive records, always keeping window endpoints and the SAME raw ledger. At scale2 these root strides correspond to reference dt.25,.5,1; the old cadence corresponds to root gaps4/16. Its fourth quadrature result and change from dense are separately identified. Existing residual normalizations and historical files are preserved. No automatic refinement-progress flags are issued for this temporal-only mode. Root-sampled agreement cannot certify finer-than-root time convergence or exclude aliasing; an unresolved outcome stays unresolved, with no automatic longer run.
+
+Three distinct throughput quantities must remain separate:
+
+- Prescribed unsigned nominal mass at rho_ref=1:2*Q_command*window_duration.
+- Observed raw absolute NET aperture mass: sum over root intervals of abs(dm_blowing)+abs(dm_suction), after spatial reduction within each aperture. This retains reversals between root intervals that abs(window-net) loses. Within-aperture or within-root/substep reversals remain unresolved by this ledger. The legacy raw_gross_mass_over_nominal field retains its old abs(window-net)/ONE-aperture-nominal definition; it is not this new quantity.
+- Sparse reconstructed absolute Q/M: true-arc quadrature of abs(u.n) and abs(rho*u.n), using each existing linear/quadratic ray estimate, followed by old-cadence time integration. This is estimator-dependent measured-field evidence, not exact wall truth, not dense-root quadrature, and not a prescribed nominal flow.
+
+Global stock-minus-raw mass balance is reported per root interval and summed per window, in reference mass units. Raw total-minus-wall/aperture partition discrepancies are also separate. Neither is bundled into the CV temporal error, and neither is called a proven raw-extractor defect. Source/geometry/state validity, both signed and gross budgets, old failures, and physics_validation_pass=false remain intact.
+
+Planning envelope from the earlier52-second800-step pilot: s1 60–240s, s2 600–2400s, with conservative post-READY caps1200/5400s. Scale2 has4x cells and4x root observations over the same reference horizon; sparse saving reduces output, not all CPU/PCIe observation cost. These are preparation estimates, not measured timings. Root owns startup/compilation timeout and GPU serialization. No GPU/remote action was taken to prepare this option.
+
+Budget enforcement preflights the projected retained file sizes before replacing each snapshot/window report or the sample+metadata pair. If32MiB would be exceeded, staged replacements are removed, the previous verified sample/hash-metadata pair remains intact, and execution stops. Temporary compression files need additional short-lived disk space and are distinct from the32MiB retained-evidence cap. This protects budget failures; it is not a filesystem crash-recovery transaction. Both raw partition identities, total−wall−aperture and aperture−blowing−suction, are saved separately from stock/raw and CV residuals.