Merge native 92b8afe scaled N256 Taylor-Green diagnostic into claude/shear-wave

Bundle celeris-scaled-tg-92b8afe-base-eec4677.bundle (SHA256 9e593384...)
verified with git bundle verify; merged without rewriting history.
Conflicts resolved by retaining both additions: run_case keeps the
shear-wave flow helpers/receipt block and the scaled_n256 diagnostic block,
with scaled_n256 restricted to --flow taylor_green (mutually exclusive with
shear_wave); test_projected_pairs keeps the explicit 'taylor_green'
verify_source argument and 92b8afe's per-scheme selector expectation.

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

tests/validation/taylor_green/run_case.py

@@ -19,6 +19,7 @@ BUILD_CAPTURE_SHA256 = "3dbaa6547cb0a4cb1541054f3b64ad8b6e18cc70527ac6166e56b944
 REFERENCE_HARNESS = "11901a7f77557a901e017a171eeae1758d584fa5"
 INITIALIZATION = "physical FP64 equilibrium G at actual cell centers; rho=1+3p"
 SHEAR_WAVE_SHA256 = "81d5c8ee60864372887cddf9239580c82fb6750d956038f1e3ee9de61aa4e877"
+SCALED_DIAGNOSTIC = "scaled_n256"
 
 
 def flow_functions(flow="taylor_green"):
@@ -176,10 +177,12 @@ def main():
     p.add_argument("--run-gpu", action="store_true")
     p.add_argument("--dry-run", action="store_true")
     p.add_argument("--re", type=int, choices=[100, 1000], required=True)
-    p.add_argument("--n", type=int, choices=[32, 64, 128, 256], required=True)
+    p.add_argument("--n", type=int, choices=[32, 64, 128, 256, 512], required=True)
     p.add_argument("--depth", type=int, choices=[1, 2, 3], required=True)
     p.add_argument("--output", type=Path, required=True)
     p.add_argument("--explosion", choices=["constant", "projected_linear"], default="constant")
+    p.add_argument("--diagnostic", choices=[SCALED_DIAGNOSTIC],
+                   help="explicit four-case N256/fine512 same-placement diagnostic")
     p.add_argument("--early-pressure", action="store_true",
                    help="also save 65 scalar pressure samples at t*=k*.001875, k=0..64")
     p.add_argument("--flow", choices=["taylor_green", "shear_wave"], default="taylor_green")
@@ -191,6 +194,15 @@ def main():
         p.error("Output already exists; choose a new path to retain prior evidence")
     if args.explosion != "constant" and args.depth != 2:
         p.error("projected_linear requires depth 2")
+    if args.diagnostic:
+        cases = {(256, 1, "constant"), (512, 1, "constant"),
+                 (256, 2, "constant"), (256, 2, "projected_linear")}
+        if args.flow != "taylor_green":
+            p.error("--diagnostic scaled_n256 requires --flow taylor_green")
+        if args.re != 100 or (args.n, args.depth, args.explosion) not in cases or not args.early_pressure:
+            p.error("scaled_n256 requires one of its four Re100 cases and --early-pressure")
+    elif args.n == 512:
+        p.error("N512 requires --diagnostic scaled_n256")
     selected = os.environ.get("CUDA_VISIBLE_DEVICES", "")
     if not args.dry_run and (not args.run_gpu or not selected or "," in selected or selected == "-1"):
         p.error("--run-gpu and exactly one explicit CUDA_VISIBLE_DEVICES are required")
@@ -199,7 +211,8 @@ def main():
     source = verify_source(repo, args.expected_revision, args.flow)
     runtime = runtime_source(repo)
     if args.dry_run:
-        print(json.dumps(dict(source=source, runtime_source=runtime, dry_run=True)))
+        print(json.dumps(dict(source=source, runtime_source=runtime, dry_run=True,
+                              **({"diagnostic": args.diagnostic} if args.diagnostic else {}))))
         return 0
     from CelerisLab.cuda.context import CudaContext
     from CelerisLab.lbm.blocks import BlockLayout2D
@@ -252,6 +265,8 @@ def main():
         report.update(flow=args.flow, mode=list(shear_wave.MODE),
                       polarization=shear_wave.E.tolist(), angle_deg=shear_wave.ANGLE_DEG,
                       phase=shear_wave.PHI, eps=shear_wave.eps(args.n))
+    if args.diagnostic:
+        report["diagnostic"] = args.diagnostic
     args.output.parent.mkdir(parents=True, exist_ok=True)
     def save():
         temporary = args.output.with_suffix(args.output.suffix + ".tmp")