fix: restore sh -c wrapper for llamafile execution on Linux

The previous commit changed the execution from using 'sh -c' to directly
executing './llamafile', which broke CI tests on Linux (ubuntu-latest).

llamafile is an APE (Actually Portable Executable) that requires shell
execution on Linux. This commit restores the 'sh -c' wrapper for non-Windows
systems while maintaining LoRA adapter support.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: rishi-jat

pkg/lib/harness/llm-harness.go

@@ -90,25 +90,31 @@ func (harness *LLMHarness) Start(modelPath string, loraPaths []string) (err erro
 	}
 	var cmd *exec.Cmd
 
-	args := []string{
-		"--server",
-		"--model", modelPath,
-		"--host", harness.Host,
-		"--port", fmt.Sprintf("%d", harness.Port),
-		"--path", uiHome,
-		"--gpu", "AUTO",
-		"--nobrowser",
-		"--unsecure",
-	}
-
-	for _, loraPath := range loraPaths {
-		args = append(args, "--lora", loraPath)
-	}
-
 	if runtime.GOOS == "windows" {
+		args := []string{
+			"--server",
+			"--model", modelPath,
+			"--host", harness.Host,
+			"--port", fmt.Sprintf("%d", harness.Port),
+			"--path", uiHome,
+			"--gpu", "AUTO",
+			"--nobrowser",
+			"--unsecure",
+		}
+		for _, loraPath := range loraPaths {
+			args = append(args, "--lora", loraPath)
+		}
 		cmd = exec.Command("./llamafile.exe", args...)
 	} else {
-		cmd = exec.Command("./llamafile", args...)
+		// Build command string for sh -c (required for APE binaries on Linux)
+		loraArgs := ""
+		for _, loraPath := range loraPaths {
+			loraArgs += fmt.Sprintf(" --lora %s", loraPath)
+		}
+		cmd = exec.Command("sh", "-c",
+			fmt.Sprintf("./llamafile --server --model %s --host %s --port %d --path %s --gpu AUTO --nobrowser --unsecure%s",
+				modelPath, harness.Host, harness.Port, uiHome, loraArgs),
+		)
 	}
 
 	cmd.Dir = harnessPath