b5a6297d

By: Michael Lynch <git@mtlynch.io>

Add behavior-rich media store writes

Let media consumers produce output through a Write callback so storage adapters
own seekability and S3 metadata. Cover local and S3 adapter behavior without
filesystem writes, and document the contract and implementation path.
Codeberg
configuredevShellx86_64-linuxbackendbackend-devcheck-bashcheck-frontendcheck-go-formattingcheck-go-test-packagescheck-trailing-newlinecheck-trailing-whitespacedeploy-to-flydiagramdocker-imagee2e-testsgo-testsimport-from-tinybeansjs-testslint-sqllittle-momentslittle-moments-devx86_64-linux