test(engine): restore the clamped fill pins the code produces

0719476 re-pinned the Fill, Strip and Vertical Remnant clamp-zone
characterization digests to 9BF5FC7FC47364A9, but that layout never
reproduced: CI and local Linux runs at that commit and since give the
previous digests unchanged, so Cross-platform tests has failed on every
push since. Clamp clearance defaults to the bottom edge spacing, which
these plates already used, so their layouts were never expected to move.

Checked the produced layouts before restoring them: all four strategies
place 40 parts inside the work area with no NestLayoutCheck violations
against the clamp clearance.

OpenNest.Engine.Tests/Jobs/FillStackCharacterizationTests.cs

@@ -338,9 +338,9 @@ public class FillStackCharacterizationTests
     // --- interactive fill beside clamps ---
 
     [Theory]
-    [InlineData("Fill", 40, "9BF5FC7FC47364A9")]
-    [InlineData("Strip", 40, "9BF5FC7FC47364A9")]
-    [InlineData("Vertical Remnant", 40, "9BF5FC7FC47364A9")]
+    [InlineData("Fill", 40, "9B3EFF9B72243576")]
+    [InlineData("Strip", 40, "9B3EFF9B72243576")]
+    [InlineData("Vertical Remnant", 40, "039C0D607166D805")]
     [InlineData("Horizontal Remnant", 40, "C1E81564A620302A")]
     public void FillItem_WithClampZones_PinnedLayout(
         string strategy,