fix(docs): drop deprecated baseUrl from tsconfig

TypeScript 6.0 marks `baseUrl` as deprecated, which Vitest's typecheck
turns into a hard CI failure. The docs `paths` already use relative
`./` notation, so removing `baseUrl` is a no-op for resolution.

The landmine sat dormant until commit e58ea4d added the first
`*.test.ts` under `packages/docs/`, which caused Vitest to actually
load the docs `tsconfig.test.json` for typechecking on every run.

Author: colinhacks

packages/docs/tsconfig.json

@@ -1,6 +1,5 @@
 {
   "compilerOptions": {
-    "baseUrl": ".",
     "target": "ESNext",
     "lib": ["dom", "dom.iterable", "esnext"],
     "allowJs": true,