test: add harness and some examples

[Salazareo]

running tests with coverage now in PRs

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	16.1%	2828 / 17560
🔵	Statements	15.69%	2990 / 19049
🔵	Functions	15.24%	454 / 2978
🔵	Branches	8.21%	1152 / 14019

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
extensions/devWatcher.ts	0%	0%	0%	0%	9-300
extensions/thumbnails.ts	32.25%	16.39%	18.18%	33.72%	19-49, 53, 56, 90-93, 99-121, 126-168, 174-179
src/backend/server.ts	49.86%	34.4%	43.58%	50.43%	85-86, 100-105, 120-126, 171-184, 187, 208-212, 235-236, 239-248, 251-255, 263, 266, 269, 275, 298, 305-311, 314-365, 388-417, 434-452, 466-468, 487-491, 503-504, 507, 529-534, 537-543, 546-552, 555-561, 571-573, 584, 588-590, 605, 611-647, 660-680, 687-688, 719-756
src/backend/testUtil.ts	100%	100%	100%	100%
src/backend/types.ts	100%	100%	100%	100%
src/backend/clients/database/SqliteDatabaseClient.ts	43.28%	29.68%	20.68%	43.41%	158-162, 177, 202-205, 212, 232-234, 244-528, 539-542, 561
src/backend/clients/dynamodb/DDBClient.ts	74.58%	52.47%	77.77%	74.41%	30-32, 37, 50-51, 58, 67, 85-86, 90-99, 149, 153, 158, 185, 201-207, 211-215, 294-297, 303-304, 319-353, 403-411
src/backend/services/metering/MeteringService.ts	88.7%	84.94%	87.5%	88.98%	78-79, 278-298, 439-457, 703, 825-827, 856, 863, 911-966
src/backend/services/selfhosted/DefaultUserService.ts	13.15%	6.25%	33.33%	11.76%	47-129
src/backend/util/nativeImport.ts	100%	100%	100%	100%

Generated in workflow #2 for commit bf4f37d by the Vitest Coverage Report Action