Phase 1: Fix IPC compilation errors + freestyle sidecar

- Fix HyperTwistIPCProcessManager: remove invalid CreatePipe(nullptr) call
- Fix HyperTwistIPCProcessManager: const-correctness for IsProcRunning
- Fix HyperTwistSolverOracleLibrary: remove stale variable reference
- Add HyperTwistHttpSpeechClient header for freestyle STT integration (1B)
- Add freestyle_sidecar.bat launcher script

Solvers/freestyle/freestyle_sidecar.bat

@@ -0,0 +1,38 @@
+@echo off
+setlocal
+
+REM HyperTwist Freestyle STT Sidecar Launcher
+REM Phase 1B: Runs freestyle server as external HTTP sidecar process
+
+cd /d "%~dp0\..\..\.external\freestyle"
+
+REM Check if pnpm is available
+where pnpm >nul 2>nul
+if errorlevel 1 (
+    echo ERROR: pnpm not found. Install pnpm first:
+    echo   npm install -g pnpm
+    exit /b 1
+)
+
+REM Install dependencies if node_modules is missing
+if not exist "node_modules" (
+    echo Installing freestyle dependencies...
+    call pnpm install
+    if errorlevel 1 (
+        echo ERROR: pnpm install failed
+        exit /b 1
+    )
+)
+
+REM Build the server package
+cd apps\server
+echo Building freestyle server...
+call pnpm build
+if errorlevel 1 (
+    echo ERROR: Server build failed
+    exit /b 1
+)
+
+REM Start the server
+echo Starting freestyle server on port 8787...
+node dist\index.js

UnrealHyperTwist/Source/UnrealHyperTwist/Private/HyperTwistIPC/HyperTwistIPCProcessManager.cpp

@@ -38,11 +38,6 @@ FHyperTwistIPCResult UHyperTwistIPCProcessManager::RunProcess(const FHyperTwistI
     if (Options.bCaptureOutput)
     {
         FPlatformProcess::CreatePipe(ReadPipe, WritePipe);
-        if (Options.bRedirectInput)
-        {
-            FPlatformProcess::CreatePipe(StdErrPipe, nullptr);
-        }
-
         ProcessHandle = FPlatformProcess::CreateProc(
             *Options.ExecutablePath,
             *Params,
@@ -213,7 +208,7 @@ bool UHyperTwistIPCProcessManager::TerminateProcess(int32 ProcessId)
 
 bool UHyperTwistIPCProcessManager::IsProcessRunning(int32 ProcessId) const
 {
-    const FActiveProcess* Proc = ActiveProcesses.Find(ProcessId);
+    FActiveProcess* Proc = ActiveProcesses.Find(ProcessId);
     if (!Proc)
     {
         return false;

UnrealHyperTwist/Source/UnrealHyperTwist/Private/HyperTwistIPC/HyperTwistSolverOracleLibrary.cpp

@@ -88,11 +88,9 @@ bool UHyperTwistSolverOracleLibrary::CompareSolvers(const FString& FaceletString
 {
     // rob-twophase result
     TArray<FString> RobTwophaseMoves = UHyperTwistSolverLibrary::SolveClassicState(FaceletString, 5000, 25, 1);
-    TArray<FString> RobMoves;
-    RobTwophaseSolution.ParseIntoArrayWS(RobMoves);
 
     // cahidenes result
     TArray<FString> CahidenesMoves = SolveWithCahidenesOracle(FaceletString);
 
-    return RobMoves.Num() == CahidenesMoves.Num();
+    return RobTwophaseMoves.Num() == CahidenesMoves.Num();
 }

UnrealHyperTwist/Source/UnrealHyperTwist/Public/HyperTwistIPC/HyperTwistHttpSpeechClient.h

@@ -0,0 +1,51 @@
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Kismet/BlueprintFunctionLibrary.h"
+#include "Http.h"
+#include "HyperTwistHttpSpeechClient.generated.h"
+
+USTRUCT(BlueprintType)
+struct FHyperTwistSpeechTranscriptResult
+{
+    GENERATED_BODY()
+
+    UPROPERTY(BlueprintReadOnly, Category = "HyperTwist|Speech")
+    bool bSuccess = false;
+
+    UPROPERTY(BlueprintReadOnly, Category = "HyperTwist|Speech")
+    FString Transcript;
+
+    UPROPERTY(BlueprintReadOnly, Category = "HyperTwist|Speech")
+    FString ErrorMessage;
+
+    UPROPERTY(BlueprintReadOnly, Category = "HyperTwist|Speech")
+    float Confidence = 0.0f;
+};
+
+/**
+ * HTTP client for freestyle-voice sidecar integration.
+ * Communicates with the freestyle Node.js server running on localhost:8787.
+ */
+UCLASS()
+class UNREALHYPERTWIST_API UHyperTwistHttpSpeechClient : public UBlueprintFunctionLibrary
+{
+    GENERATED_BODY()
+
+public:
+    UFUNCTION(BlueprintCallable, Category = "HyperTwist|Speech", meta = (WorldContext = "WorldContextObject"))
+    static void SendDictationAudio(UObject* WorldContextObject, const TArray<uint8>& PCM16Data,
+        const FOnSpeechTranscriptReceived& OnComplete);
+
+    UFUNCTION(BlueprintCallable, Category = "HyperTwist|Speech")
+    static bool IsFreestyleSidecarReachable();
+
+    UFUNCTION(BlueprintPure, Category = "HyperTwist|Speech")
+    static FString GetFreestyleSidecarUrl();
+
+    /** Parse move notation from transcript. e.g. "R prime" -> R counter-clockwise */
+    UFUNCTION(BlueprintCallable, Category = "HyperTwist|Speech")
+    static TArray<FString> ParseMoveNotation(const FString& Transcript);
+};
+
+DECLARE_DYNAMIC_DELEGATE_OneParam(FOnSpeechTranscriptReceived, const FHyperTwistSpeechTranscriptResult&, Result);