Refactor runner and installation scripts for improved functionality

- Removed the `--disable-hiprt` flag from the runner command, simplifying the rendering options for users.
- Updated the `jiggablend-runner` script and README to reflect the removal of the HIPRT control flag, enhancing clarity in usage instructions.
- Enhanced the installation script to provide clearer examples for running the jiggablend manager and runner, improving user experience during setup.
- Implemented a more robust GPU backend detection mechanism, allowing for better compatibility with various hardware configurations.

internal/runner/tasks/render.go

@@ -104,15 +104,10 @@ func (p *RenderProcessor) Process(ctx *Context) error {
 	renderFormat := "EXR"
 
 	if ctx.ShouldForceCPU() {
-		v := ctx.GetBlenderVersion()
-		major := parseBlenderMajor(v)
-		isPre4 := v != "" && major >= 0 && major < 4
 		if ctx.ForceCPURendering {
 			ctx.Info("Runner compatibility flag is enabled: forcing CPU rendering for this job")
 		} else if ctx.GPUDetectionFailed {
-			ctx.Info("GPU backend detection failed at startup—we could not determine whether this machine has HIP (AMD) or NVIDIA GPUs, so rendering will use CPU to avoid compatibility issues")
-		} else if isPre4 && ctx.HasHIP {
-			ctx.Info("Blender < 4.x has no official HIP support: using CPU rendering only")
+			ctx.Info("GPU backend detection failed at startup—we could not determine available GPU backends, so rendering will use CPU to avoid compatibility issues")
 		} else {
 			ctx.Info("GPU lockout active: using CPU rendering only")
 		}
@@ -195,7 +190,6 @@ func (p *RenderProcessor) createRenderScript(ctx *Context, renderFormat string)
 		settingsMap = make(map[string]interface{})
 	}
 	settingsMap["force_cpu"] = ctx.ShouldForceCPU()
-	settingsMap["disable_hiprt"] = ctx.DisableHIPRT
 	settingsJSON, err := json.Marshal(settingsMap)
 	if err == nil {
 		if err := os.WriteFile(renderSettingsFilePath, settingsJSON, 0644); err != nil {
@@ -277,6 +271,9 @@ func (p *RenderProcessor) runBlender(ctx *Context, blenderBinary, blendFile, out
 				}
 			}
 		}
+		if err := scanner.Err(); err != nil {
+			log.Printf("Error reading stdout: %v", err)
+		}
 	}()
 
 	// Stream stderr and watch for GPU error lines
@@ -297,6 +294,9 @@ func (p *RenderProcessor) runBlender(ctx *Context, blenderBinary, blendFile, out
 				}
 			}
 		}
+		if err := scanner.Err(); err != nil {
+			log.Printf("Error reading stderr: %v", err)
+		}
 	}()
 
 	// Wait for completion