feat(context): pin decisionJournal source type through compression

core/context/src/main/kotlin/com/correx/core/context/builder/DefaultContextPackBuilder.kt

@@ -14,7 +14,7 @@ class DefaultContextPackBuilder(
     private val compressor: ContextCompressor
 ) : ContextPackBuilder {
 
-    private val neverDropSourceTypes = setOf("steeringNote", "eventHistory")
+    private val neverDropSourceTypes = setOf("steeringNote", "eventHistory", "decisionJournal")
 
     override fun build(
         id: ContextPackId,
@@ -78,6 +78,7 @@ class DefaultContextPackBuilder(
         "artifact" -> CompressionStrategy.Artifact
         "steeringNote" -> CompressionStrategy.SteeringNote
         "eventHistory" -> CompressionStrategy.EventHistory
+        "decisionJournal" -> CompressionStrategy.EventHistory
         else -> CompressionStrategy.Conversation()
     }
 }

core/context/src/test/kotlin/DecisionJournalPinningTest.kt

@@ -0,0 +1,41 @@
+import com.correx.core.context.builder.DefaultContextPackBuilder
+import com.correx.core.context.compression.DefaultContextCompressor
+import com.correx.core.context.model.ContextEntry
+import com.correx.core.context.model.ContextLayer
+import com.correx.core.context.model.TokenBudget
+import com.correx.core.events.types.ContextEntryId
+import com.correx.core.events.types.ContextPackId
+import com.correx.core.events.types.SessionId
+import com.correx.core.events.types.StageId
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
+
+class DecisionJournalPinningTest {
+
+    private val compressor = DefaultContextCompressor()
+    private val builder = DefaultContextPackBuilder(compressor)
+
+    private val sessionId = SessionId("s1")
+    private val stageId = StageId("stage-1")
+    private val packId = ContextPackId("pack-1")
+
+    @Test
+    fun `decisionJournal entry survives an under-budget build`() {
+        val entries = listOf(
+            ContextEntry(
+                id = ContextEntryId("journal-1"),
+                layer = ContextLayer.L1,
+                content = "Decision: approved plan",
+                sourceType = "decisionJournal",
+                sourceId = "journal-1",
+                tokenEstimate = 100
+            )
+        )
+        val pack = builder.build(packId, sessionId, stageId, entries, TokenBudget(limit = 10))
+        val allRetained = pack.layers.values.flatten()
+        assertTrue(
+            allRetained.any { it.sourceType == "decisionJournal" },
+            "decisionJournal entry must be retained even when budget is exceeded"
+        )
+    }
+}