v15.2.0-canary.21

Core Changes

• fix: Merge link header from middleware with the ones from React: #73431
• Restore and enhance error handling for hanging inputs in "use cache": #74652

Misc Changes

• Remove endpoint.write_to_disk() in favor of standardized endpoint.output(): #75059

Credits

Huge thanks to @amannn, @wbinnssmith, and @unstubbable for helping!