kernels: name compilation entries by storage route (uniform.cu, blocked.cu)

kernel_v2.cu -> uniform.cu (whole-domain NX/NY, Simulation) and
blocks.cu -> blocked.cu (one block window, every blocked level), with
InitTubeFlow_v2 -> InitTubeFlow. All live callers, include comments,
CONFIG.md, lifecycle doc and current-tree tests move together; no alias.
refinement.cu keeps its name until the dense-route decision.
Historical-revision tooling that names the old files (LES source pins,
timing/J campaign runners, TG run_case, supported_settings citations at
888c8038, development notes) is unchanged on purpose.
No arithmetic change; the PTX symbol InitTubeFlow_v2 is renamed.

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

tests/validation/multigrid/test_block_stepper.py

@@ -171,7 +171,7 @@ class CpuContracts(unittest.TestCase):
                 patch.object(cuda, "mem_alloc") as alloc, patch.object(cuda, "memcpy_htod") as upload:
             with self.assertRaisesRegex(RuntimeError, "layout mismatch"):
                 PeriodicBlockStepper(config(), layout, context=context)
-            self.assertEqual(compile_kernel.call_args.kwargs["source"], "blocks.cu")
+            self.assertEqual(compile_kernel.call_args.kwargs["source"], "blocked.cu")
             alloc.assert_not_called()
             upload.assert_not_called()