fix(kernel+infra): tool approval gate and executor cleanup

- SessionOrchestrator: wire T2/T3/T4 approval gate before tool execution;
  emit OrchestrationPausedEvent/ApprovalRequestedEvent, await decision,
  return rejection as ERROR context entry so LLM sees the denial;
  propagate tool ERROR entries as StageExecutionResult.Failure
- SandboxedToolExecutor: remove dead code and simplify
- InfrastructureModule: minor wiring cleanup
- LlamaCppInferenceProvider / build.gradle: related build fixes

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

@@ -238,6 +238,10 @@ abstract class SessionOrchestrator(
             toolRounds < MAX_TOOL_ROUNDS
         ) {
             val toolEntries = dispatchToolCalls(sessionId, stageId, inferenceResult.response.toolCalls)
+            val firstError = toolEntries.firstOrNull { it.content.startsWith("ERROR:") }
+            if (firstError != null) {
+                return StageExecutionResult.Failure(firstError.content.removePrefix("ERROR: "), retryable = true)
+            }
             val allEntries = currentContext.layers.values.flatten() + toolEntries
             currentContext = contextPackBuilder.build(
                 id = ContextPackId(UUID.randomUUID().toString()),
@@ -297,6 +301,63 @@ abstract class SessionOrchestrator(
                     request = request,
                 ),
             )
+            val requiresApproval = when (tier) {
+                Tier.T0, Tier.T1 -> false
+                Tier.T2, Tier.T3, Tier.T4 -> true
+            }
+            if (requiresApproval) {
+                val requestId = ApprovalRequestId(UUID.randomUUID().toString())
+                val domainRequest = DomainApprovalRequest(
+                    id = requestId,
+                    tier = tier,
+                    validationReportId = ValidationReportId(UUID.randomUUID().toString()),
+                    riskSummaryId = null,
+                    timestamp = Clock.System.now(),
+                )
+                emit(sessionId, OrchestrationPausedEvent(sessionId, stageId, "APPROVAL_PENDING"))
+                emit(
+                    sessionId,
+                    ApprovalRequestedEvent(
+                        requestId = requestId,
+                        tier = tier,
+                        validationReportId = domainRequest.validationReportId,
+                        riskSummaryId = null,
+                        sessionId = sessionId,
+                        stageId = stageId,
+                        projectId = null,
+                    ),
+                )
+                val deferred = CompletableDeferred<ApprovalDecision>()
+                pendingApprovals[requestId] = deferred
+                val decision = try {
+                    deferred.await()
+                } finally {
+                    pendingApprovals.remove(requestId)
+                }
+                emitDecisionResolved(sessionId, domainRequest, decision)
+                if (!decision.isApproved) {
+                    val sourceId = toolCall.id ?: invocationId.value
+                    val assistantEntry = ContextEntry(
+                        id = ContextEntryId(UUID.randomUUID().toString()),
+                        layer = ContextLayer.L2,
+                        sourceType = "assistantToolCall",
+                        sourceId = sourceId,
+                        content = Json.encodeToString(ToolCallRequest.serializer(), toolCall),
+                        tokenEstimate = toolCall.function.arguments.length / 4,
+                    )
+                    val reason = decision.reason ?: "approval denied"
+                    val resultEntry = ContextEntry(
+                        id = ContextEntryId(UUID.randomUUID().toString()),
+                        layer = ContextLayer.L2,
+                        sourceType = "toolResult",
+                        sourceId = sourceId,
+                        content = "ERROR: $reason",
+                        tokenEstimate = reason.length / 4,
+                    )
+                    return@flatMap listOf(assistantEntry, resultEntry)
+                }
+                emit(sessionId, OrchestrationResumedEvent(sessionId, stageId))
+            }
             val result = executor.execute(request)
             val sourceId = toolCall.id ?: invocationId.value
             val assistantEntry = ContextEntry(

infrastructure/inference/llama_cpp/build.gradle

@@ -17,8 +17,6 @@ dependencies {
     implementation project(':core:context')
     implementation project(':infrastructure:inference:commons')
 
-    implementation("com.fasterxml.jackson.core:jackson-databind:2.17.0")
-    implementation("com.fasterxml.jackson.module:jackson-module-kotlin:2.17.0")
     implementation "io.ktor:ktor-client-core:$ktor_version"
     implementation "io.ktor:ktor-client-cio:$ktor_version"
     implementation "io.ktor:ktor-client-content-negotiation:$ktor_version"

infrastructure/inference/llama_cpp/src/main/kotlin/com/correx/infrastructure/inference/llama/cpp/LlamaCppInferenceProvider.kt

@@ -25,7 +25,9 @@ import io.ktor.client.request.setBody
 import io.ktor.http.ContentType
 import io.ktor.http.contentType
 import io.ktor.serialization.kotlinx.json.json
+import kotlinx.serialization.encodeToString
 import kotlinx.serialization.json.Json
+import org.slf4j.LoggerFactory
 
 private const val DEFAULT_REQUEST_TIMEOUT_MS = 60_000L
 
@@ -42,7 +44,23 @@ private fun defaultHttpClient(): HttpClient = HttpClient(CIO) {
     install(HttpTimeout) {
         requestTimeoutMillis = DEFAULT_REQUEST_TIMEOUT_MS
     }
+    install(ContentNegotiation) {
+        json(
+            Json {
+                ignoreUnknownKeys = true
+                explicitNulls = false
+                encodeDefaults = true
+            },
+        )
+    }
 }
+private val json = Json {
+    ignoreUnknownKeys = true
+    explicitNulls = false
+    encodeDefaults = true
+}
+
+private val log = LoggerFactory.getLogger(LlamaCppInferenceProvider::class.java)
 
 @Suppress("TooGenericExceptionCaught", "MagicNumber")
 class LlamaCppInferenceProvider(
@@ -80,12 +98,17 @@ class LlamaCppInferenceProvider(
             tools = request.tools.takeIf { it.isNotEmpty() },
         )
 
+        val encoded = json.encodeToString(body)
+        log.debug("sending request to llm: {}", encoded)
+
         val response = httpClient.post("$baseUrl/v1/chat/completions") {
             contentType(ContentType.Application.Json)
             accept(ContentType.Application.Json)
-            setBody(body)
+            setBody(encoded)
         }.body<ChatCompletionResponse>()
 
+        log.debug("got response from llm: {}", response)
+
         val message = response.choices.first().message
         val finishReason = when (response.choices.first().finishReason.lowercase()) {
             "length" -> FinishReason.Length

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

@@ -1,6 +1,5 @@
 package com.correx.infrastructure
 
-import com.correx.core.approvals.domain.ApprovalEngine
 import com.correx.core.artifactstore.ArtifactStore
 import com.correx.core.events.EventDispatcher
 import com.correx.core.events.stores.EventStore
@@ -110,15 +109,11 @@ object InfrastructureModule {
 
     fun createToolExecutor(
         registry: ToolRegistry,
-        approvalEngine: ApprovalEngine,
-        eventStore: EventStore,
         eventDispatcher: EventDispatcher,
         workDir: Path,
     ): ToolExecutor = SandboxedToolExecutor(
         delegate = DispatchingToolExecutor(registry),
         registry = registry,
-        approvalEngine = approvalEngine,
-        eventStore = eventStore,
         eventDispatcher = eventDispatcher,
         workDir = workDir,
     )

infrastructure/tools/src/main/kotlin/com/correx/infrastructure/tools/SandboxedToolExecutor.kt

@@ -1,28 +1,15 @@
 package com.correx.infrastructure.tools
 
 import com.correx.core.approvals.Tier
-import com.correx.core.approvals.domain.ApprovalEngine
-import com.correx.core.approvals.model.ApprovalContext
-import com.correx.core.approvals.model.ApprovalGrant
-import com.correx.core.approvals.model.ApprovalScopeIdentity
-import com.correx.core.approvals.model.DomainApprovalRequest
 import com.correx.core.events.EventDispatcher
-import com.correx.core.events.events.ApprovalGrantCreatedEvent
 import com.correx.core.events.events.EventPayload
-import com.correx.core.events.events.StoredEvent
 import com.correx.core.events.events.ToolExecutionCompletedEvent
 import com.correx.core.events.events.ToolExecutionFailedEvent
-import com.correx.core.events.events.ToolExecutionRejectedEvent
 import com.correx.core.events.events.ToolExecutionStartedEvent
 import com.correx.core.events.events.ToolReceipt
 import com.correx.core.events.events.ToolRequest
-import com.correx.core.events.stores.EventStore
-import com.correx.core.events.types.ApprovalRequestId
 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 com.correx.core.sessions.ApprovalMode
 import com.correx.core.tools.contract.FileAffectingTool
 import com.correx.core.tools.contract.Tool
 import com.correx.core.tools.contract.ToolExecutor
@@ -41,8 +28,6 @@ import java.util.*
 class SandboxedToolExecutor(
     private val delegate: ToolExecutor,
     private val registry: ToolRegistry,
-    private val approvalEngine: ApprovalEngine,
-    private val eventStore: EventStore,
     private val eventDispatcher: EventDispatcher,
     private val workDir: Path = Path.of("/tmp/correx-sandbox"),
 ) : ToolExecutor {
@@ -61,26 +46,7 @@ class SandboxedToolExecutor(
                 recoverable = false,
             )
 
-        // 2. approval check for T2-T4
-        val requiresApproval = when (tool.tier) {
-            Tier.T0, Tier.T1 -> false
-            Tier.T2, Tier.T3, Tier.T4 -> true
-        }
-
-        if (requiresApproval) {
-            val sessionEvents = eventStore.read(sessionId)
-            val decision = evaluateApproval(tool, sessionId, request.stageId, sessionEvents)
-            if (!decision.isApproved) {
-                emitRejected(sessionId, invocationId, toolName, tool.tier, decision.reason ?: "approval denied")
-                return@withContext ToolResult.Failure(
-                    invocationId = invocationId,
-                    reason = decision.reason ?: "approval denied",
-                    recoverable = false,
-                )
-            }
-        }
-
-        // 3. emit started
+        // 2. emit started
         emitStarted(sessionId, invocationId, toolName)
 
         // 4. create working dir
@@ -121,45 +87,6 @@ class SandboxedToolExecutor(
         }
     }
 
-    // --- approval ---
-
-    private fun evaluateApproval(
-        tool: Tool,
-        sessionId: SessionId,
-        stageId: StageId,
-        sessionEvents: List<StoredEvent>,
-    ) = approvalEngine.evaluate(
-        request = DomainApprovalRequest(
-            id = ApprovalRequestId(UUID.randomUUID().toString()),
-            tier = tool.tier,
-            validationReportId = ValidationReportId(UUID.randomUUID().toString()),
-            riskSummaryId = null,
-            timestamp = Clock.System.now(),
-            causationId = null,
-            correlationId = null,
-        ),
-        context = ApprovalContext(
-            identity = ApprovalScopeIdentity(sessionId, stageId, null),
-            mode = ApprovalMode.PROMPT,
-        ),
-        grants = extractGrants(sessionEvents),
-        now = Clock.System.now(),
-    )
-
-    private fun extractGrants(events: List<StoredEvent>): List<ApprovalGrant> =
-        events
-            .mapNotNull { it.payload as? ApprovalGrantCreatedEvent }
-            .map { e ->
-                ApprovalGrant(
-                    id = e.grantId,
-                    scope = e.scope,
-                    permittedTiers = e.permittedTiers,
-                    reason = e.reason,
-                    timestamp = Clock.System.now(),
-                    expiresAt = e.expiresAt,
-                )
-            }
-
     // --- backup/restore ---
 
     /**
@@ -209,14 +136,6 @@ class SandboxedToolExecutor(
 
     // --- event emission ---
 
-    private suspend fun emitRejected(
-        sessionId: SessionId,
-        invocationId: ToolInvocationId,
-        toolName: String,
-        tier: Tier,
-        reason: String,
-    ) = emit(sessionId, ToolExecutionRejectedEvent(invocationId, sessionId, toolName, tier, reason))
-
     private suspend fun emitStarted(
         sessionId: SessionId,
         invocationId: ToolInvocationId,