Introduced tstyche for type checking and to guard against unintentional API changes

[smallsaucepan]

Introduced TSTyche for type checking and to guard against unintentional API changes. For example, a test like this would have caught #3006

This is a second PR to compare with a similar solution using tsd #3015

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[smallsaucepan]

Example error output:

> @turf/line-offset@7.3.3 test:types /Users/james/turf/packages/turf-line-offset
> tstyche

···· TSTyche 6.2.0 at /Users/james/turf/packages/turf-line-offset

uses TypeScript 5.8.3 with ./tsconfig.json

fail ./test/types.tst.ts

Error: Type 'Feature<LineString, { [name: string]: any; } | null> | Feature<MultiLineString, { [name: string]: any; } | null>' is not the same as type 'Feature<LineString, GeoJsonProperties>'.

  34 |  * broadened the return type which is likely to be a breaking change.
  35 |  */
  36 | expect(lineOffset(line, 50)).type.toBe<Feature<LineString>>();
     |                                        ~~~~~~~~~~~~~~~~~~~
  37 | expect(lineOffset(multiLine, 50)).type.toBe<Feature<MultiLineString>>();
  38 |

       at ./test/types.tst.ts:36:40

Error: Type 'Feature<LineString, { [name: string]: any; } | null> | Feature<MultiLineString, { [name: string]: any; } | null>' is not the same as type 'Feature<MultiLineString, GeoJsonProperties>'.

  35 |  */
  36 | expect(lineOffset(line, 50)).type.toBe<Feature<LineString>>();
  37 | expect(lineOffset(multiLine, 50)).type.toBe<Feature<MultiLineString>>();
     |                                             ~~~~~~~~~~~~~~~~~~~~~~~~
  38 |

       at ./test/types.tst.ts:37:45

Targets:    1 failed, 1 total
Test files: 1 failed, 1 total
Assertions: 2 failed, 5 passed, 7 total
Duration:   1.5s

[mfedderly]

This PR seems pretty reasonable as well. I'm swayed by the argument that tsd is relatively unmaintained and tstyche is the replacement. It also doesn't ship as a dependency to our users, so worst case we just have to rework Turf itself. It seems like most of these libraries are standardizing around pretty similar APIs so worst case we can probably translate to another tool later if we have to.

[mrazauskas]

Thanks. I appreciate your choice! Please ping me if there are any questions in the future.