Bump Vite build target to es2022 and fail CI on rolldown warnings

[silverwind]

1. Bump Vite build target to es2022

Top-level await added in d5831b9 requires es2022. This fixes the TOLERATED_TRANSFORM warning emitted on each build:

[TOLERATED_TRANSFORM] Warning: Top-level await is not available in the configured target environment.
   ╭─[ web_src/js/render/plugins/frontend-openapi-swagger.ts:2:1 ]
   │
 2 │ await import("../../../css/swagger.css");

Browser support for es2022 is available in Chrome 94+, Firefox 93+ and Safari 15+.

2. Fail the build on rolldown warnings in CI

Adds an onwarn handler in commonRolldownOptions that throws when env.CI is set, so warnings can be noticed in CI. Locally, the default handler still prints them without aborting to not break user builds.

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This PR was written with the help of Claude Opus 4.7

[silverwind]

@wolfbeast fyi, this will be for v1.27.

[wxiaoguang]

Actually, I am not sure whether it really needs es2022

This await import("../../../css/swagger.css"); is only for loading CSS files, and the JS is executed in type=module. So I don't know whether the "await" is really a problem, or just a wrong warning from Vite

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OK, it seems that it becomes standard in es2022, while some browsers supported it ahead.

Maybe it's better to find a way to avoid such top-level await and make the CSS importing work (if possible)

Details

[wxiaoguang]

The top-level await import is also caused by incorrect Vite manifest parser, it makes the CSS importing very messy.

[wxiaoguang]

No need to use es2022

-> Fix top-level await #37272