feat(journal): compaction-aware DecisionJournalRenderer

core/journal/src/main/kotlin/com/correx/core/journal/DecisionJournalRenderer.kt

@@ -3,12 +3,17 @@ package com.correx.core.journal
 import com.correx.core.journal.model.DecisionJournalState
 
 class DecisionJournalRenderer(private val keepLast: Int = 40) {
-    fun render(state: DecisionJournalState): String {
+    fun render(state: DecisionJournalState, summaryText: String? = null): String {
-        if (state.records.isEmpty()) return ""
+        if (state.records.isEmpty() && summaryText == null) return ""
-        val shown = state.records.takeLast(keepLast)
         return buildString {
             appendLine("## Decision history (chronological — ground truth)")
-            shown.forEach { appendLine("- [${it.kind}] ${it.summary}") }
+            if (summaryText != null) {
+                appendLine(summaryText)
+                if (state.lowSalienceOmittedCount > 0) {
+                    appendLine("+${state.lowSalienceOmittedCount} routine transitions/retries omitted")
+                }
+            }
+            state.records.takeLast(keepLast).forEach { appendLine("- [${it.kind}] ${it.summary}") }
         }.trimEnd()
     }
 }

core/journal/src/test/kotlin/com/correx/core/journal/DecisionJournalRendererTest.kt

@@ -0,0 +1,80 @@
+package com.correx.core.journal
+
+import com.correx.core.journal.model.DecisionJournalState
+import com.correx.core.journal.model.DecisionKind
+import com.correx.core.journal.model.DecisionRecord
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
+
+class DecisionJournalRendererTest {
+
+    private val renderer = DecisionJournalRenderer()
+
+    private fun record(seq: Long, kind: DecisionKind = DecisionKind.INTENT, summary: String = "summary-$seq") =
+        DecisionRecord(sequence = seq, kind = kind, summary = summary)
+
+    @Test
+    fun `empty state with no summaryText returns empty string`() {
+        val state = DecisionJournalState()
+        assertEquals("", renderer.render(state))
+    }
+
+    @Test
+    fun `uncompacted state renders records without omitted line`() {
+        val state = DecisionJournalState(
+            records = listOf(record(1), record(2)),
+        )
+        val result = renderer.render(state)
+        assertTrue(result.contains("- [INTENT] summary-1"))
+        assertTrue(result.contains("- [INTENT] summary-2"))
+        assertFalse(result.contains("omitted"))
+    }
+
+    @Test
+    fun `summaryText appears before records`() {
+        val state = DecisionJournalState(
+            records = listOf(record(1)),
+            lowSalienceOmittedCount = 3,
+        )
+        val result = renderer.render(state, summaryText = "Compaction summary here")
+        val lines = result.lines()
+        val headerIdx = lines.indexOfFirst { it.startsWith("## Decision history") }
+        val summaryIdx = lines.indexOfFirst { it == "Compaction summary here" }
+        val recordIdx = lines.indexOfFirst { it.startsWith("- [INTENT]") }
+        assertTrue(headerIdx >= 0)
+        assertTrue(summaryIdx > headerIdx)
+        assertTrue(recordIdx > summaryIdx)
+    }
+
+    @Test
+    fun `count line appears when lowSalienceOmittedCount is positive`() {
+        val state = DecisionJournalState(
+            records = listOf(record(1)),
+            lowSalienceOmittedCount = 5,
+        )
+        val result = renderer.render(state, summaryText = "Some summary")
+        assertTrue(result.contains("+5 routine transitions/retries omitted"))
+    }
+
+    @Test
+    fun `no count line when lowSalienceOmittedCount is zero with summaryText`() {
+        val state = DecisionJournalState(
+            records = listOf(record(1)),
+            lowSalienceOmittedCount = 0,
+        )
+        val result = renderer.render(state, summaryText = "Some summary")
+        assertFalse(result.contains("omitted"))
+    }
+
+    @Test
+    fun `summaryText with empty records list renders header and summary`() {
+        val state = DecisionJournalState(records = emptyList(), lowSalienceOmittedCount = 2)
+        val result = renderer.render(state, summaryText = "Compacted summary")
+        assertTrue(result.contains("## Decision history"))
+        assertTrue(result.contains("Compacted summary"))
+        assertTrue(result.contains("+2 routine transitions/retries omitted"))
+        assertFalse(result.contains("- ["))
+    }
+}