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.

internal/runner/api/jobconn.go

@@ -301,7 +301,12 @@ func (j *JobConnection) OutputUploaded(taskID int64, fileName string) {
 }
 
 // Complete sends task completion to the manager.
-func (j *JobConnection) Complete(taskID int64, success bool, errorMsg error) {
+// errorMsg must be JSON-encoded as a string: encoding an error interface
+// marshals to {} and the manager fails to unmarshal task_complete, which
+// previously surfaced as a generic "WebSocket connection lost" with no retries.
+// freeRequeue asks the manager to requeue a failure without incrementing retry_count
+// (used when this attempt newly armed GPU lockout).
+func (j *JobConnection) Complete(taskID int64, success bool, errorMsg error, freeRequeue bool) {
 	if j.conn == nil {
 		log.Printf("Cannot send task complete: WebSocket connection is nil")
 		return
@@ -310,13 +315,20 @@ func (j *JobConnection) Complete(taskID int64, success bool, errorMsg error) {
 	j.writeMu.Lock()
 	defer j.writeMu.Unlock()
 
+	data := map[string]interface{}{
+		"task_id": taskID,
+		"success": success,
+	}
+	if errorMsg != nil {
+		data["error"] = errorMsg.Error()
+	}
+	if freeRequeue {
+		data["free_requeue"] = true
+	}
+
 	msg := map[string]interface{}{
-		"type": "task_complete",
-		"data": map[string]interface{}{
-			"task_id": taskID,
-			"success": success,
-			"error":   errorMsg,
-		},
+		"type":      "task_complete",
+		"data":      data,
 		"timestamp": time.Now().Unix(),
 	}
 	if err := j.conn.WriteJSON(msg); err != nil {