Improve regression test quality: OSWEC 1000s duration, RM3 output precision, and updated reference data

- Increase OSWEC regular wave test duration from 240s to 1000s for regression test report plots across all 16 wave conditions
- Increase RM3 regular wave output precision from 4 to 8 decimal places to eliminate "steppy" plate heave plots
- Fix sphere irregular waves eta consistency test: increase eta export precision from 10 to 17 significant digits to eliminate 1e-8 spikes caused by double-precision truncation during export/reimport
- Regenerate all affected reference data (OSWEC x16, RM3, sphere consistency) from latest simulation results

Author: dav-og

build.ps1

@@ -73,8 +73,7 @@ if ($Help) {
 
     Write-Host "LONG TESTS:" -ForegroundColor Yellow
     Write-Host "  Set `$env:HYDROCHRONO_LONG_TESTS='1' before running ctest to use extended"
-    Write-Host "  simulation durations (e.g. OSWEC reg waves: 240s -> 1000s) for publication-"
-    Write-Host "  quality regression reports.`n"
+    Write-Host "  simulation durations for publication-quality regression reports.`n"
 
     Write-Host "CONFIG FILE:" -ForegroundColor Yellow
     Write-Host '  { "ChronoDir": "C:/path/to/chrono/build/cmake" }' -ForegroundColor Gray