feat: surface risk rationale to operator in approval prompt

Carry the full RiskSummary (level, signals, rationale) inline on
ApprovalRequestedEvent instead of discarding it after assessment. The two
server-side DTO builders (live ApprovalCoordinator path and replay
DomainEventMapper path) now render real risk level, recommended action,
signal factors, and the [code] rationale lines into the approval WebSocket
message, with a consistent enum-name fallback when no assessment ran (tool
path). RiskSummary/RiskSignal made @Serializable for event embedding;
shared RiskSummary.toDto() lives next to RiskSummaryDto.

core/approvals/src/main/kotlin/com/correx/core/approvals/model/DomainApprovalRequest.kt

@@ -2,6 +2,7 @@ package com.correx.core.approvals.model
 
 import com.correx.core.approvals.Tier
 import com.correx.core.approvals.UserSteering
+import com.correx.core.events.risk.RiskSummary
 import com.correx.core.events.types.ApprovalRequestId
 import com.correx.core.events.types.CausationId
 import com.correx.core.events.types.CorrelationId
@@ -16,6 +17,7 @@ data class DomainApprovalRequest(
     val tier: Tier,
     val validationReportId: ValidationReportId,
     val riskSummaryId: RiskSummaryId?,
+    val riskSummary: RiskSummary? = null,
     val timestamp: Instant,
     val causationId: CausationId? = null,
     val correlationId: CorrelationId? = null,

core/events/src/main/kotlin/com/correx/core/events/events/ApprovalEvents.kt

@@ -5,6 +5,7 @@ import com.correx.core.approvals.ApprovalStatus
 import com.correx.core.approvals.GrantScope
 import com.correx.core.approvals.Tier
 import com.correx.core.approvals.UserSteering
+import com.correx.core.events.risk.RiskSummary
 import com.correx.core.events.types.ApprovalDecisionId
 import com.correx.core.events.types.ApprovalRequestId
 import com.correx.core.events.types.GrantId
@@ -24,6 +25,7 @@ data class ApprovalRequestedEvent(
     val tier: Tier,
     val validationReportId: ValidationReportId,
     val riskSummaryId: RiskSummaryId?,
+    val riskSummary: RiskSummary? = null,
     val sessionId: SessionId,
     val stageId: StageId?,
     val projectId: ProjectId?,

core/events/src/main/kotlin/com/correx/core/events/risk/RiskSignal.kt

@@ -1,8 +1,23 @@
 package com.correx.core.events.risk
 
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
 sealed class RiskSignal {
+    @Serializable
+    @SerialName("CycleWithoutExit")
     data class CycleWithoutExit(val cycleId: String) : RiskSignal()
+
+    @Serializable
+    @SerialName("RepeatedFailure")
     data class RepeatedFailure(val reason: String, val count: Int) : RiskSignal()
+
+    @Serializable
+    @SerialName("ValidationErrors")
     data class ValidationErrors(val errorCount: Int) : RiskSignal()
+
+    @Serializable
+    @SerialName("InferenceTimeout")
     data class InferenceTimeout(val elapsedMs: Long) : RiskSignal()
 }

core/events/src/main/kotlin/com/correx/core/events/risk/RiskSummary.kt

@@ -1,5 +1,8 @@
 package com.correx.core.events.risk
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class RiskSummary(
     val level: RiskLevel,
     val signals: List<RiskSignal>,

core/events/src/test/kotlin/com/correx/core/events/EventSerializationHardeningTest.kt

@@ -4,6 +4,7 @@ import com.correx.core.approvals.ApprovalOutcome
 import com.correx.core.approvals.ApprovalStatus
 import com.correx.core.approvals.Tier
 import com.correx.core.events.events.ApprovalDecisionResolvedEvent
+import com.correx.core.events.events.ApprovalRequestedEvent
 import com.correx.core.events.events.EventPayload
 import com.correx.core.events.events.OrchestrationPausedEvent
 import com.correx.core.events.events.RiskAssessedEvent
@@ -13,13 +14,17 @@ import com.correx.core.events.events.WorkflowCompletedEvent
 import com.correx.core.events.events.WorkflowStartedEvent
 import com.correx.core.events.risk.RiskAction
 import com.correx.core.events.risk.RiskLevel
+import com.correx.core.events.risk.RiskSignal
+import com.correx.core.events.risk.RiskSummary
 import com.correx.core.events.serialization.eventJson
 import com.correx.core.events.types.ApprovalDecisionId
 import com.correx.core.events.types.ApprovalRequestId
+import com.correx.core.events.types.ProjectId
 import com.correx.core.events.types.RiskSummaryId
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
 import com.correx.core.events.types.ToolInvocationId
+import com.correx.core.events.types.ValidationReportId
 import kotlinx.datetime.Instant
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.jsonObject
@@ -110,4 +115,30 @@ class EventSerializationHardeningTest {
             eventJson.decodeFromString(EventPayload.serializer(), withExtra)
         }
     }
+
+    @Test
+    fun `ApprovalRequestedEvent with non-null riskSummary round-trips through EventPayload polymorphic serializer`() {
+        val riskSummary = RiskSummary(
+            level = RiskLevel.HIGH,
+            signals = listOf(
+                RiskSignal.ValidationErrors(errorCount = 3),
+                RiskSignal.RepeatedFailure(reason = "parse error", count = 2),
+            ),
+            recommendedAction = RiskAction.PROMPT_USER,
+            rationale = listOf("[ERR001] Schema mismatch", "[ERR002] Missing required field"),
+        )
+        val event: EventPayload = ApprovalRequestedEvent(
+            requestId = ApprovalRequestId("req-rt-1"),
+            tier = Tier.T3,
+            validationReportId = ValidationReportId("vr-rt-1"),
+            riskSummaryId = null,
+            riskSummary = riskSummary,
+            sessionId = sessionId,
+            stageId = stageId,
+            projectId = ProjectId("proj-1"),
+        )
+        val json = eventJson.encodeToString(EventPayload.serializer(), event)
+        val decoded = eventJson.decodeFromString(EventPayload.serializer(), json)
+        assertEquals(event, decoded)
+    }
 }

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/SessionOrchestrator.kt

@@ -894,6 +894,7 @@ abstract class SessionOrchestrator(
                 tier = domainRequest.tier,
                 validationReportId = domainRequest.validationReportId,
                 riskSummaryId = domainRequest.riskSummaryId,
+                riskSummary = domainRequest.riskSummary,
                 sessionId = sessionId,
                 stageId = stageId,
                 projectId = null,
@@ -938,6 +939,9 @@ abstract class SessionOrchestrator(
             ),
         )
         val riskSummaryId = RiskSummaryId(UUID.randomUUID().toString())
+        // RiskAssessedEvent records the indexed level+action summary; ApprovalRequestedEvent carries the full
+        // authoritative RiskSummary (signals + rationale). Both derive from the same assessment value so
+        // they cannot diverge.
         emit(
             sessionId,
             RiskAssessedEvent(sessionId, stageId, riskSummaryId, riskSummary.level, riskSummary.recommendedAction),
@@ -947,6 +951,7 @@ abstract class SessionOrchestrator(
             tier = riskSummary.level.toApprovalTier(),
             validationReportId = ValidationReportId(UUID.randomUUID().toString()),
             riskSummaryId = riskSummaryId,
+            riskSummary = riskSummary,
             timestamp = Clock.System.now(),
         )
     }