Migrate bench/test for area, bbox-clip, bezier-spline, and buffer

[mfedderly]

Continues the path set forth in #3038 for a few more packages.

• testFixtures is extended to handle non-geojson return values as well
• Migrate some root package.json dependencies to the pnpm catalog version
• Limited the node --test execution to test.ts only, which avoid conflicts in packages with tstyche type testing

Side notes that I discovered while working on this:

• colorize gets implemented in many different test.ts files. Consolidating this is out of scope for this push because they're slightly different
• TypeScript 6 is going to have us change how we're referencing index.ts in each of these test/bench files
• TypeScript 6 is also going to force us to be explicit about when we're including @types/node
• In order to support the boolean packages, we need to handle true and false test subdirectories. Perhaps this is just a different test runner

Depends on #3061

[mfedderly]

area() actually just returns a number, so it makes sense to have test/out/*.json and not .geojson.

[mfedderly]

The build is failing here because node@18 doesn't support working against TypeScript files directly.