Probe fidelity options

- Print measured-window stage totals from EngineMetrics as IRIS_GENPROBE_STAGES
- Time each context prefill task into its prefill timer
- Add gated generation counters for generator evaluations, corner starcasts and hydrology lookups
- Add -PprobeHydrologyPreplan to plan the probe area's hydrology tiles before warmup
- Add -PprobeHistoryRouter to generate through a generation-history router and registry contract
- Add -PprobeProductionBuffers to generate into production-equivalent block and biome hunks
- Print the mantle radius as IRIS_GENPROBE_MANTLE

core/src/test/java/art/arcane/iris/generation/runtime/EngineMetricsStageTotalsTest.java

@@ -0,0 +1,47 @@
+package art.arcane.iris.generation.runtime;
+
+import org.junit.Test;
+
+import java.util.Map;
+import java.util.Set;
+
+import static org.junit.Assert.assertEquals;
+
+public final class EngineMetricsStageTotalsTest {
+    @Test
+    public void stageTotalsAccumulatePastTheRollingWindow() {
+        EngineMetrics metrics = new EngineMetrics(2);
+        metrics.getTerrain().put(1.5D);
+        metrics.getTerrain().put(2.5D);
+        metrics.getTerrain().put(4D);
+
+        EngineMetrics.StageTotal terrain = metrics.stageTotals().get("terrain");
+
+        assertEquals(8D, terrain.millis(), 0D);
+        assertEquals(3L, terrain.samples());
+        assertEquals(3.25D, metrics.getTerrain().getAverage(), 0D);
+    }
+
+    @Test
+    public void stageTotalsSinceAnEarlierSnapshotCoverOnlyTheLaterPuts() {
+        EngineMetrics metrics = new EngineMetrics(4);
+        metrics.getCarveResolve().put(3D);
+        EngineMetrics.StageTotal before = metrics.stageTotals().get("carve.resolve");
+        metrics.getCarveResolve().put(5D);
+        metrics.getCarveResolve().put(7D);
+
+        EngineMetrics.StageTotal window = metrics.stageTotals().get("carve.resolve").since(before);
+
+        assertEquals(12D, window.millis(), 0D);
+        assertEquals(2L, window.samples());
+    }
+
+    @Test
+    public void stageTotalsNameEveryPulledTimer() {
+        EngineMetrics metrics = new EngineMetrics(1);
+        Map<String, EngineMetrics.StageTotal> totals = metrics.stageTotals();
+
+        assertEquals(Set.copyOf(metrics.pull().keySet()), Set.copyOf(totals.keySet()));
+        assertEquals(metrics.pull().size(), totals.size());
+    }
+}