AI video generation startup Runway has raised a $315 million Series E round, nearly doubling its valuation to $5.3 billion, a source familiar with the matter told TechCrunch.  The fresh funds will allow Runway to “pre-train the next generation of world models and bring them to new products and industries,” per a company blog post announcing the raise. World models are AI systems that construct internal representations of an environment so they can plan for future events, and many top minds