Move openapi-example.yaml to test/fixtures and flesh out with edge cases

[Copilot]

Summary

Moves openapi-example.yaml from the repository root into test/fixtures/openapi-example.yaml and expands it with a comprehensive set of OpenAPI edge cases to better exercise the code generator and server.

Changes

• test/fixtures/openapi-example.yaml – new home for the file, greatly expanded:
  • Full CRUD resource: GET /users, POST /users, GET/PUT/PATCH/DELETE /users/{userId}
  • Polymorphic event ingestion at POST /events using oneOf + allOf + discriminator
  • Nullable fields, enums, integer formats (int64, double) on GET /products/{productId}
  • File upload via multipart/form-data at POST /uploads
  • Cookie parameter + deprecated endpoint at GET /legacy/items
  • Multiple response content types (application/json, text/csv, application/pdf) at GET /reports/{reportId}
  • 204-only health-check at GET /ping
  • Free-form additionalProperties object at PUT /metadata
  • anyOf on product attributes
  • Multiple reusable $ref response components (BadRequest, Unauthorized, NotFound, InternalServerError)
  • Three security schemes (basicAuth, bearerAuth, apiKey) with global security + per-endpoint overrides
  • Pagination query parameters with minimum/maximum/default constraints
  • Response headers (x-total-count, x-next-page, x-rate-limit-remaining)
• package.json – go:example script updated to new path
• test/app.test.ts – two openApiPath references updated
• test/typescript-generator/generate.test.ts – generate() call updated
• test/typescript-generator/__snapshots__/generate.test.ts.snap – regenerated
• .changeset/move-openapi-example-to-fixtures.md – changeset entry added

Manual acceptance tests

• yarn go:example starts the server successfully against the new fixture path with no errors
• GET /users returns a 200 with the withUsers example payload
• POST /events with a ClickEvent body returns 202 Accepted
• GET /products/42 returns a 200 with a Product-shaped response
• GET /ping returns 204 with no body
• Existing routes unrelated to the moved file (e.g. petstore) behave unchanged