next: remove taskr
The previous commit wired build-scripts/ as the default pipeline while
keeping taskfile*.js + taskr devDeps around as a fallback. With no
internal caller remaining, drop the fallback.
Removed:
- packages/next/taskfile.js, taskfile-swc.js, taskfile-ncc.js,
taskfile-webpack.js, taskfile-watch.js
- patches/taskr@1.1.0.patch (taskr is unmaintained; we were carrying
a local patch against it)
- taskr, @taskr/clear, @taskr/esnext devDependencies
- update-error-codes script now invokes the new build:compile +
build:check-errors scripts instead of pnpm taskr
