Refactor installation and runner scripts for enhanced usability and security

- Updated the installation script to clarify that production wrappers do not include fixed test secrets, improving user guidance for local testing.
- Modified the jiggablend-manager and jiggablend-runner scripts to remove fixed test configurations, emphasizing the use of local test credentials via `make init-test`.
- Enhanced error handling in the runner script to ensure that an API key is provided, improving security and user feedback.
- Added new flags and options for the runner, including sandboxing capabilities and GPU ray tracing control, enhancing flexibility for users.
- Improved README documentation to reflect changes in usage and configuration, ensuring users have clear instructions for setup and execution.

pkg/types/types.go

@@ -137,7 +137,7 @@ type CreateJobRequest struct {
 	RenderSettings  *RenderSettings `json:"render_settings,omitempty"`   // Optional: Override blend file render settings
 	UploadSessionID *string         `json:"upload_session_id,omitempty"` // Optional: Session ID from file upload
 	UnhideObjects   *bool           `json:"unhide_objects,omitempty"`    // Optional: Enable unhide tweaks for objects/collections
-	EnableExecution *bool           `json:"enable_execution,omitempty"`  // Optional: Enable auto-execution in Blender (adds --enable-autoexec flag, defaults to false)
+	EnableExecution *bool           `json:"enable_execution,omitempty"`  // Optional: allow Python autoexec inside the .blend (--enable-autoexec). Job blender_addons/ always install when present.
 	BlenderVersion  *string         `json:"blender_version,omitempty"`   // Optional: Override Blender version (e.g., "4.2" or "4.2.3")
 }
 
@@ -231,7 +231,7 @@ type BlendMetadata struct {
 	SceneInfo         SceneInfo         `json:"scene_info"`
 	MissingFilesInfo  *MissingFilesInfo `json:"missing_files_info,omitempty"`
 	UnhideObjects     *bool             `json:"unhide_objects,omitempty"`   // Enable unhide tweaks for objects/collections
-	EnableExecution   *bool             `json:"enable_execution,omitempty"` // Enable auto-execution in Blender (adds --enable-autoexec flag, defaults to false)
+	EnableExecution   *bool             `json:"enable_execution,omitempty"` // Allow .blend Python autoexec (--enable-autoexec); separate from blender_addons/ install
 	BlenderVersion    string            `json:"blender_version,omitempty"`  // Detected or overridden Blender version (e.g., "4.2" or "4.2.3")
 }