test: guard what the handlers claim and what the entry costs

[skjnldsv]

Two checks that stop a gap reopening, rather than tests of anything new.

What the handlers claim

Reads the mime lists straight out of the models and asserts each one is opened by a test. A claim nobody exercises is how the audio handler ended up offering eleven types while a single fixture sat in the playground that no spec ever touched.

Types that cannot be covered from the playground are listed with a reason, and the list is guarded in both directions: an excuse for a type no longer claimed fails, and so does an excuse for a type some test does open. So the excuses have to be argued for rather than inherited.

It found three things on its first run, which is the best argument for it:

• video/webm was claimed and untested. There was a webm fixture, but it was audio.
• audio/aac was claimed and untested. The m4a fixture is audio/mp4, a different type.
• image/apng was excused because the server has no .apng mapping. That is true and it is a different concern: the playground proves the handler renders one, and whether an upload ever arrives as that mime belongs to the server suite. Excuse removed.

Both gaps now have fixtures, and a small video spec to open them.

What the entry costs

check-bundle-size.mjs already walked the static graph with a gzip budget and a list of chunks that must stay lazy. It stopped at the package boundary: it only followed relative specifiers, so import 'konva' at the top level would have sailed through.

That is the mistake most likely to be made here, and it has come close twice. The editor sits behind defineAsyncComponent and the score renderer behind an import inside its own component, and until now nothing checked either arrangement. Two megabytes on every Files page is a bad way to find out.

dependencies: @nextcloud/capabilities, @nextcloud/files, @nextcloud/l10n/gettext, @nextcloud/logger, vue
Within budget.

I checked it fails rather than assuming: importing opensheetmusicdisplay at the top of lib/index.ts makes it exit 1 and name the package.

One thing worth saying: I wrote a second script for this before noticing the existing one did most of it. Deleted, and the check went where it belonged.

378 unit, 86 e2e.

👾 This pull request was assisted by Claude Code, commits carry an Assisted-by trailer.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.62%. Comparing base (9eaac8e) to head (a078daf).

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #57   +/-   ##
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  Coverage   88.62%   88.62%           
=======================================
  Files          39       39           
  Lines        2743     2743           
  Branches      561      561           
=======================================
  Hits         2431     2431           
  Misses        305      305           
  Partials        7        7           

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