feat: wire L3 write path via Embedder into router

Introduces Embedder contract in core:inference with a NoopEmbedder
default (zero vector) and wires both Embedder and L3MemoryStore into
DefaultRouterFacade. Each ChatTurnEvent emission now embeds the turn
content and writes a corresponding L3MemoryEntry, so cross-session
memory is captured at the source of truth (the event emission point).

InfrastructureModule defaults to NoopEmbedder + InMemoryL3MemoryStore
so the system runs without an external embedding model or vector store
wired. The TurboVec adapter stays unwired for now; switching to it is
a configuration concern (Epic 12 config layer).

Also gitignores apps/tui/logs/ (Kotlin TUI runtime logs, pre-Go rewrite).

.gitignore

@@ -74,3 +74,6 @@ correx-tui.log
 current.log
 # Go TUI build output
 apps/tui-go/bin/
+
+# TUI runtime logs (Kotlin TUI, pre-Go rewrite)
+apps/tui/logs/

core/inference/src/main/kotlin/com/correx/core/inference/Embedder.kt

@@ -0,0 +1,20 @@
+package com.correx.core.inference
+
+/**
+ * Interface for computing vector embeddings of text.
+ * Implementations provide pre-computed vectors for similarity search and retrieval.
+ */
+interface Embedder {
+    /**
+     * Dimensionality of the returned embeddings.
+     */
+    val dimension: Int
+
+    /**
+     * Compute a vector embedding for the given text.
+     *
+     * @param text The text to embed.
+     * @return A vector of [dimension] floats.
+     */
+    suspend fun embed(text: String): FloatArray
+}

core/inference/src/main/kotlin/com/correx/core/inference/NoopEmbedder.kt

@@ -0,0 +1,8 @@
+package com.correx.core.inference
+
+/**
+ * Returns a zero vector. Lets the L3 write path run without an embedding model wired.
+ */
+class NoopEmbedder(override val dimension: Int = 1536) : Embedder {
+    override suspend fun embed(text: String): FloatArray = FloatArray(dimension)
+}

core/router/src/main/kotlin/com/correx/core/router/RouterFacade.kt

@@ -10,10 +10,13 @@ import com.correx.core.events.types.EventId
 import com.correx.core.events.types.InferenceRequestId
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
+import com.correx.core.inference.Embedder
 import com.correx.core.inference.InferenceRequest
 import com.correx.core.inference.InferenceRouter
 import com.correx.core.inference.ModelCapability
 import com.correx.core.inference.ResponseFormat
+import com.correx.core.router.l3.L3MemoryEntry
+import com.correx.core.router.l3.L3MemoryStore
 import com.correx.core.router.model.RouterConfig
 import com.correx.core.router.model.RouterResponse
 import kotlinx.datetime.Clock
@@ -34,6 +37,8 @@ class DefaultRouterFacade(
     private val eventStore: EventStore,
     private val config: RouterConfig,
     private val validateSteering: (suspend (String) -> String?)? = null,
+    private val embedder: Embedder,
+    private val l3MemoryStore: L3MemoryStore,
 ) : RouterFacade {
 
     override suspend fun onUserInput(
@@ -96,6 +101,18 @@ class DefaultRouterFacade(
                 ),
             ),
         )
+
+        val vector = embedder.embed(content)
+        l3MemoryStore.store(
+            L3MemoryEntry(
+                id = turnId,
+                sessionId = sessionId,
+                turnId = turnId,
+                text = content,
+                vector = vector,
+                timestampMs = nowMs,
+            )
+        )
     }
 
     private suspend fun emitSteeringNote(sessionId: SessionId, content: String, effectiveStageId: StageId) {

infrastructure/src/main/kotlin/com/correx/infrastructure/InfrastructureModule.kt

@@ -9,9 +9,11 @@ import com.correx.core.artifactstore.ArtifactStore
 import com.correx.core.events.EventDispatcher
 import com.correx.core.events.stores.EventStore
 import com.correx.core.inference.CapabilityScore
+import com.correx.core.inference.Embedder
 import com.correx.core.inference.InferenceProvider
 import com.correx.core.inference.InferenceRouter
 import com.correx.core.inference.ModelCapability
+import com.correx.core.inference.NoopEmbedder
 import com.correx.core.inference.Tokenizer
 import com.correx.core.router.DefaultRouterContextBuilder
 import com.correx.core.router.DefaultRouterFacade
@@ -19,6 +21,8 @@ import com.correx.core.router.DefaultRouterReducer
 import com.correx.core.router.DefaultRouterRepository
 import com.correx.core.router.RouterFacade
 import com.correx.core.router.RouterProjector
+import com.correx.core.router.l3.InMemoryL3MemoryStore
+import com.correx.core.router.l3.L3MemoryStore
 import com.correx.core.router.model.RouterConfig
 import com.correx.core.sessions.projections.replay.DefaultEventReplayer
 import com.correx.core.tools.contract.ToolExecutor
@@ -129,17 +133,23 @@ object InfrastructureModule {
         workDir = workDir,
     )
 
+    fun createNoopEmbedder(dimension: Int = 1536): Embedder = NoopEmbedder(dimension)
+
+    fun createInMemoryL3MemoryStore(): L3MemoryStore = InMemoryL3MemoryStore()
+
     fun createRouterFacade(
         eventStore: EventStore,
         inferenceRouter: InferenceRouter,
         config: RouterConfig = RouterConfig(),
         tokenizer: Tokenizer? = null,
+        embedder: Embedder = createNoopEmbedder(),
+        l3MemoryStore: L3MemoryStore = createInMemoryL3MemoryStore(),
     ): RouterFacade {
         val reducer = DefaultRouterReducer()
         val projector = RouterProjector(reducer)
         val replayer = DefaultEventReplayer(eventStore, projector)
         val repository = DefaultRouterRepository(replayer)
         val contextBuilder = DefaultRouterContextBuilder(config, tokenizer)
-        return DefaultRouterFacade(repository, contextBuilder, inferenceRouter, eventStore, config)
+        return DefaultRouterFacade(repository, contextBuilder, inferenceRouter, eventStore, config, null, embedder, l3MemoryStore)
     }
 }

testing/deterministic/src/test/kotlin/RouterFacadeTest.kt

@@ -10,12 +10,14 @@ import com.correx.core.events.types.ProviderId
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
 import com.correx.core.inference.CapabilityScore
+import com.correx.core.inference.Embedder
 import com.correx.core.inference.FinishReason
 import com.correx.core.inference.InferenceProvider
 import com.correx.core.inference.InferenceRequest
 import com.correx.core.inference.InferenceResponse
 import com.correx.core.inference.InferenceRouter
 import com.correx.core.inference.ModelCapability
+import com.correx.core.inference.NoopEmbedder
 import com.correx.core.inference.ProviderHealth
 import com.correx.core.inference.ResponseFormat
 import com.correx.core.inference.TokenUsage
@@ -26,6 +28,9 @@ import com.correx.core.router.RouterContextBuilder
 import com.correx.core.router.RouterFacade
 import com.correx.core.router.RouterProjector
 import com.correx.core.router.RouterRepository
+import com.correx.core.router.l3.InMemoryL3MemoryStore
+import com.correx.core.router.l3.L3MemoryStore
+import com.correx.core.router.l3.L3Query
 import com.correx.core.router.model.RouterConfig
 import com.correx.core.router.model.RouterResponse
 import com.correx.core.router.model.RouterState
@@ -127,6 +132,8 @@ class RouterFacadeTest {
             inferenceRouter = mockInferenceRouter("steering response"),
             eventStore = mockStore,
             config = RouterConfig(tokenBudget = TokenBudget(limit = 5000)),
+            embedder = NoopEmbedder(dimension = 8),
+            l3MemoryStore = InMemoryL3MemoryStore(),
         )
         facade.onUserInput(sessionId = SessionId("test-session"), input = "Hello!", mode = ChatMode.STEERING)
         assertEquals(3, mockStore.appendedEvents.size)
@@ -161,6 +168,8 @@ class RouterFacadeTest {
             inferenceRouter = mockInferenceRouter("router reply"),
             eventStore = eventStore,
             config = RouterConfig(tokenBudget = TokenBudget(limit = 5000)),
+            embedder = NoopEmbedder(dimension = 8),
+            l3MemoryStore = InMemoryL3MemoryStore(),
         )
         val sessionId = SessionId("history-session")
         facade.onUserInput(sessionId = sessionId, input = "first message")
@@ -199,6 +208,8 @@ class RouterFacadeTest {
             inferenceRouter = mockInferenceRouter("response"),
             eventStore = eventStore,
             config = RouterConfig(tokenBudget = TokenBudget(limit = 5000)),
+            embedder = NoopEmbedder(dimension = 8),
+            l3MemoryStore = InMemoryL3MemoryStore(),
         )
         facade.onUserInput(sessionId = SessionId("session-A"), input = "message A")
         facade.onUserInput(sessionId = SessionId("session-B"), input = "message B")
@@ -237,6 +248,8 @@ class RouterFacadeTest {
             inferenceRouter = mockInferenceRouter("inference response"),
             eventStore = mockEventStore(),
             config = RouterConfig(tokenBudget = TokenBudget(limit = 5000)),
+            embedder = NoopEmbedder(dimension = 8),
+            l3MemoryStore = InMemoryL3MemoryStore(),
         )
         facade.onUserInput(sessionId = SessionId("test-session"), input = "Hello!")
         assertEquals(1, capturedState.size)
@@ -261,6 +274,8 @@ class RouterFacadeTest {
             inferenceRouter = mockInferenceRouter("response"),
             eventStore = mockEventStore(),
             config = RouterConfig(tokenBudget = TokenBudget(limit = 4200)),
+            embedder = NoopEmbedder(dimension = 8),
+            l3MemoryStore = InMemoryL3MemoryStore(),
         )
         facade.onUserInput(sessionId = SessionId("test-session"), input = "Hello!")
         assertEquals(1, capturedBudget.size)
@@ -294,6 +309,8 @@ class RouterFacadeTest {
             inferenceRouter = mockInferenceRouter,
             eventStore = mockEventStore(),
             config = RouterConfig(tokenBudget = TokenBudget(limit = 5000)),
+            embedder = NoopEmbedder(dimension = 8),
+            l3MemoryStore = InMemoryL3MemoryStore(),
         )
         facade.onUserInput(sessionId = SessionId("test-session"), input = "Hello!")
         assertEquals(stateStageId, capturedStageId[0])
@@ -325,6 +342,8 @@ class RouterFacadeTest {
             inferenceRouter = mockInferenceRouter,
             eventStore = mockEventStore(),
             config = RouterConfig(tokenBudget = TokenBudget(limit = 5000)),
+            embedder = NoopEmbedder(dimension = 8),
+            l3MemoryStore = InMemoryL3MemoryStore(),
         )
         facade.onUserInput(sessionId = SessionId("test-session"), input = "Hello!")
         assertEquals(StageId("none"), capturedStageId[0])
@@ -351,6 +370,8 @@ class RouterFacadeTest {
             inferenceRouter = mockInferenceRouter,
             eventStore = mockEventStore(),
             config = RouterConfig(tokenBudget = TokenBudget(limit = 5000)),
+            embedder = NoopEmbedder(dimension = 8),
+            l3MemoryStore = InMemoryL3MemoryStore(),
         )
         facade.onUserInput(sessionId = SessionId("s1"), input = "first")
         facade.onUserInput(sessionId = SessionId("s1"), input = "second")
@@ -379,6 +400,8 @@ class RouterFacadeTest {
             inferenceRouter = mockInferenceRouter,
             eventStore = mockEventStore(),
             config = RouterConfig(tokenBudget = TokenBudget(limit = 5000)),
+            embedder = NoopEmbedder(dimension = 8),
+            l3MemoryStore = InMemoryL3MemoryStore(),
         )
         facade.onUserInput(sessionId = SessionId("test-session"), input = "Hello!")
         val req = capturedRequests[0]
@@ -438,6 +461,8 @@ class RouterFacadeTest {
             },
             eventStore = mockEventStore(),
             config = RouterConfig(tokenBudget = TokenBudget(limit = 5000)),
+            embedder = NoopEmbedder(dimension = 8),
+            l3MemoryStore = InMemoryL3MemoryStore(),
         )
         facade.onUserInput(sessionId = SessionId("test-session"), input = "Hello!")
     }
@@ -462,6 +487,8 @@ class RouterFacadeTest {
             },
             eventStore = mockEventStore(),
             config = RouterConfig(tokenBudget = TokenBudget(limit = 5000)),
+            embedder = NoopEmbedder(dimension = 8),
+            l3MemoryStore = InMemoryL3MemoryStore(),
         )
         facade.onUserInput(sessionId = SessionId("test-session"), input = "Hello!")
         val req = capturedRequests[0]
@@ -479,6 +506,29 @@ class RouterFacadeTest {
         assertEquals(3, mockStore.appendedEvents.size)
     }
 
+    @Test
+    fun `CHAT round-trip stores user and router turns in L3 memory`(): Unit = runBlocking {
+        val mockStore = mockEventStore()
+        val l3Store = InMemoryL3MemoryStore()
+        val embedder = NoopEmbedder(dimension = 8)
+        val facade = facadeWithMocks(
+            eventStore = mockStore,
+            chatMode = ChatMode.CHAT,
+            embedder = embedder,
+            l3MemoryStore = l3Store,
+        )
+        val sessionId = SessionId("test-session")
+        facade.onUserInput(sessionId = sessionId, input = "Hello!")
+        val hits = l3Store.query(
+            L3Query(
+                vector = FloatArray(8),
+                k = 10,
+                sessionIdFilter = sessionId,
+            )
+        )
+        assertEquals(2, hits.size)
+    }
+
     // --------------------------------------------------------------------------
     // Helpers
     // --------------------------------------------------------------------------
@@ -488,6 +538,8 @@ class RouterFacadeTest {
     private fun facadeWithMocks(
         eventStore: EventStore,
         chatMode: ChatMode = ChatMode.CHAT,
+        embedder: Embedder = NoopEmbedder(dimension = 8),
+        l3MemoryStore: L3MemoryStore = InMemoryL3MemoryStore(),
     ): RouterFacade = DefaultRouterFacade(
         routerRepository = object : RouterRepository {
             override suspend fun getRouterState(sessionId: SessionId): RouterState =
@@ -503,6 +555,8 @@ class RouterFacadeTest {
         inferenceRouter = mockInferenceRouter("inference response"),
         eventStore = eventStore,
         config = RouterConfig(tokenBudget = TokenBudget(limit = 5000)),
+        embedder = embedder,
+        l3MemoryStore = l3MemoryStore,
     ).let { impl ->
         object : RouterFacade {
             override suspend fun onUserInput(sessionId: SessionId, input: String, mode: ChatMode): RouterResponse =