[survey] Add real-time collaborative survey design with live preview

[AI:Feature-Suggestion] ## Methodology This feature idea emerged from analyzing collaboration pain points in survey creation workflows. By studying modern collaborative tools (Figma, Google Docs) and applying those patterns to survey design, this feature addresses the common scenario where survey creation involves multiple stakeholders (researchers, subject matter experts, designers) who currently struggle with asynchronous feedback loops. ## Problem/Opportunity Survey creation often involves multiple stakeholders but current tools force sequential, inefficient collaboration: - **Marketing teams** need input from product managers on questions - **Researchers** require approval from legal/compliance teams - **Designers** want to ensure consistent branding - **Stakeholders** provide feedback through emails, comments, or meetings **Current Pain Points**: - Version control confusion ("Which survey version are we reviewing?") - Delayed feedback cycles extending project timelines - Contex