v15.4.0-canary.0

Core Changes

• Add onInvalidate option to router.prefetch: #77880
• Reserve bandwidth for most recently hovered link : #78362

Misc Changes

• docs: improve userAgent device.type example in userAgent.mdx: #78368
• fix(turbo-tasks): Make vc types use repr(transparent): #78327

Credits

Huge thanks to @acdlite, @sqidermad, and @bgw for helping!