Reworked terrain transitions

- New terrain heights meet saved boundaries while retaining local relief
- Surface water levels approach saved fluid heights across the band
- Cave and physical biome matching use a four-block seam patch
- Terrain generates once without speculative neighbor containment
- Bounded caches serve transition membership and boundary lookups
- Saved biome writes honor the selected durability policy
- Release labels and presentation code leave generation identity unchanged
- Unfinished objects retain blocks and metadata across pack changes
- Whole structure assemblies preserve pending excavation and foundations
- New placements keep pending historical pieces clear
- Transition probes cover cutovers and retained object fragments

buildSrc/src/main/java/art/arcane/iris/buildtools/GenerationRevisionScope.java

@@ -29,6 +29,10 @@ public final class GenerationRevisionScope {
             "core/src/main/java/art/arcane/iris/world/safeguard/Diagnostic.java",
             "core/src/main/java/art/arcane/iris/world/safeguard/ValueWithDiagnostics.java",
             "core/src/main/java/art/arcane/iris/diagnostics/splash/IrisSplashRenderer.java",
+            "core/src/main/java/art/arcane/iris/diagnostics/splash/IrisSplashComposer.java",
+            "core/src/main/java/art/arcane/iris/diagnostics/splash/IrisSplashPackScanner.java",
+            "adapters/modded-common/src/main/java/art/arcane/iris/modded/ModdedIrisSplash.java",
+            "adapters/bukkit/plugin/src/main/java/art/arcane/iris/command/CommandDebug.java",
             "adapters/bukkit/plugin/src/main/java/art/arcane/iris/command/CommandDeveloper.java",
             "adapters/bukkit/plugin/src/main/java/art/arcane/iris/command/CommandPregen.java",
             "adapters/bukkit/plugin/src/main/java/art/arcane/iris/command/CommandIris.java",