test: exclude dist from vitest runs in every package

[dangreen]

Why

Every package config builds its vitest exclude as [...configDefaults.exclude, './package']. In the installed vitest 5, configDefaults.exclude is only **/node_modules/** and **/.git/**, so dist is no longer excluded.

svelte-router is where it bites: svelte-package compiles everything under src, specs included, into dist. The build script cleans them with clear:dist-assets, but test:dist-types runs build:dist alone, so after pnpm test:types a stale dist/core.spec.js stays behind and the next vitest run executes it against outdated code.

Reproduced with a throwing dist/stale.spec.js in packages/svelte-router: vitest run picked it up and failed; with ./dist excluded the same file is skipped.

What

exclude: [...configDefaults.exclude, './package', './dist'] in all 19 packages/*/vite.config.js, in the style of the existing ./package entry. svelte-router keeps its extra ./.svelte-kit.

Checks

• oxlint on the configs passes.
• vitest run spot-checked in kida, react, svelte and svelte-router with unchanged counts.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.33%. Comparing base (568df71) to head (2197b35).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #254   +/-   ##
=======================================
  Coverage   83.33%   83.33%           
=======================================
  Files          98       98           
  Lines        2557     2557           
  Branches      552      552           
=======================================
  Hits         2131     2131           
  Misses        314      314           
  Partials      112      112           

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