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

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,
     )