feat(events): RepoMapComputedEvent as recorded environment observation

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

@@ -0,0 +1,28 @@
+package com.correx.core.events.events
+
+import com.correx.core.events.types.SessionId
+import kotlinx.datetime.Instant
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+/** A single ranked entry in a repo map: a path, its relevance [score], and symbol names. */
+@Serializable
+data class RepoMapEntry(
+    val path: String,
+    val score: Double,
+    val symbols: List<String> = emptyList(),
+)
+
+/**
+ * Environment observation (invariant #9): the repo map computed once at the moment it ran.
+ * Replay reads these recorded facts and never re-scans the filesystem. Paths + symbol names
+ * only — never file bodies — so it is referenced, not inlined.
+ */
+@Serializable
+@SerialName("RepoMapComputed")
+data class RepoMapComputedEvent(
+    val sessionId: SessionId,
+    val repoRoot: String,
+    val entries: List<RepoMapEntry>,
+    val computedAt: Instant,
+) : EventPayload

core/events/src/main/kotlin/com/correx/core/events/serialization/Serialization.kt

@@ -24,6 +24,7 @@ import com.correx.core.events.events.ModelUnloadedEvent
 import com.correx.core.events.events.OrchestrationPausedEvent
 import com.correx.core.events.events.OrchestrationResumedEvent
 import com.correx.core.events.events.RefinementIterationEvent
+import com.correx.core.events.events.RepoMapComputedEvent
 import com.correx.core.events.events.RetryAttemptedEvent
 import com.correx.core.events.events.RiskAssessedEvent
 import com.correx.core.events.events.StageCompletedEvent
@@ -80,6 +81,7 @@ val eventModule = SerializersModule {
         subclass(WorkflowCompletedEvent::class)
         subclass(RetryAttemptedEvent::class)
         subclass(RefinementIterationEvent::class)
+        subclass(RepoMapComputedEvent::class)
         subclass(RiskAssessedEvent::class)
         subclass(ChatSessionStartedEvent::class)
         subclass(ChatTurnEvent::class)