Drop the CommonJS build: konva has been ESM-only for some time, so the CJS
bundle could not load its own peer dependency on any runtime lacking
require(esm). It removed no capability that was actually working.

The UMD bundle stays for CDN <script> use, and now works for the first time:
the global was window["vue-konva"] with no install method, so app.use() could
never have succeeded. The README pointed at a URL that 404'd for all of 3.x.

Also fixes packaging defects that shipped in 3.4.0: declarations importing a
path package.json#files never published, and a GlobalComponents augmentation
keyed on unprefixed names that install() never registers.

scripts/check-dist.mjs guards both classes in CI, including a jsdom run of the
README's CDN snippet.