feat(kernel): RepoKnowledgeRetriever port + relevance-retrieved repo context with recency fallback

apps/server/src/main/kotlin/com/correx/apps/server/Main.kt

@@ -276,6 +276,22 @@ fun main() {
     val artifactKindRegistry = DefaultArtifactKindRegistry().also { reg ->
         configArtifactKindsEarly.forEach { reg.register(it) }
     }
+    val embedder = InfrastructureModule.createEmbedderFromConfig(correxConfig.router.embedder)
+    val l3MemoryStore = InfrastructureModule.createL3MemoryStoreFromConfig(correxConfig.router.l3)
+    // Rebuild the L3 metadata map from the ChatTurnEvent log before serving queries:
+    // persisted vectors survive restart but the metadata map does not (no-op for
+    // non-rehydratable backends like in_memory).
+    runBlocking { L3MetadataRehydrator(eventStore).rehydrate(l3MemoryStore) }
+    val repoKnowledgeRetriever: com.correx.apps.server.memory.L3RepoKnowledgeRetriever? =
+        if (correxConfig.project.enabled) {
+            com.correx.apps.server.memory.L3RepoKnowledgeRetriever(
+                embedder = embedder,
+                l3MemoryStore = l3MemoryStore,
+                repoRoot = workspaceRoot.toString(),
+            )
+        } else {
+            null
+        }
     val orchestrator = DefaultSessionOrchestrator(
         repositories = repositories,
         engines = engines,
@@ -285,13 +301,8 @@ fun main() {
         decisionJournalRepository = decisionJournalRepository,
         compactionService = journalCompactionService,
         artifactKindRegistry = artifactKindRegistry,
+        repoKnowledgeRetriever = repoKnowledgeRetriever,
     )
-    val embedder = InfrastructureModule.createEmbedderFromConfig(correxConfig.router.embedder)
-    val l3MemoryStore = InfrastructureModule.createL3MemoryStoreFromConfig(correxConfig.router.l3)
-    // Rebuild the L3 metadata map from the ChatTurnEvent log before serving queries:
-    // persisted vectors survive restart but the metadata map does not (no-op for
-    // non-rehydratable backends like in_memory).
-    runBlocking { L3MetadataRehydrator(eventStore).rehydrate(l3MemoryStore) }
     val workflowRegistry = FileSystemWorkflowRegistry(
         InfrastructureModule.createWorkflowLoader(configArtifactKindsEarly),
     )

apps/server/src/main/kotlin/com/correx/apps/server/memory/L3RepoKnowledgeRetriever.kt

@@ -0,0 +1,24 @@
+package com.correx.apps.server.memory
+
+import com.correx.core.events.events.RepoKnowledgeHit
+import com.correx.core.events.types.SessionId
+import com.correx.core.inference.Embedder
+import com.correx.core.kernel.orchestration.RepoKnowledgeRetriever
+import com.correx.core.router.l3.L3MemoryStore
+import com.correx.core.router.l3.L3Query
+
+private const val RETRIEVAL_OVERSAMPLE_FACTOR = 4
+
+class L3RepoKnowledgeRetriever(
+    private val embedder: Embedder,
+    private val l3MemoryStore: L3MemoryStore,
+    private val repoRoot: String,
+) : RepoKnowledgeRetriever {
+    override suspend fun retrieve(sessionId: SessionId, query: String, k: Int): List<RepoKnowledgeHit> {
+        val vector = embedder.embed(query)
+        return l3MemoryStore.query(L3Query(vector = vector, k = k * RETRIEVAL_OVERSAMPLE_FACTOR))
+            .filter { it.entry.turnId.startsWith("repomap:$repoRoot") }
+            .take(k)
+            .map { RepoKnowledgeHit(path = it.entry.text.substringBefore(":"), text = it.entry.text, score = it.score) }
+    }
+}