ci: export OpenAPI spec as CI artifact (#40)

[temisan0x]

Closes #40

What this does

Adds a CI step that programmatically exports the NestJS Swagger spec as downloadable artifacts (openapi.json and openapi.yaml), replacing the hardcoded stub in generate-api-docs.sh.

Changes

• Backend/src/export-spec.ts — headless NestJS bootstrap; builds the Swagger document and writes both formats to infrastructure/docs/
• Backend/package.json — adds export-spec script (ts-node -r tsconfig-paths/register src/export-spec.ts)
• infrastructure/scripts/generate-api-docs.sh — replaces hardcoded stub heredoc with npm run export-spec
• infrastructure/ci/docs-generation.yml — adds Node 20 setup, npm ci, Postgres 15 service container, correct DATABASE_* env vars, and artifact upload for openapi-spec

Why Postgres

AppModule initialises TypeORM on app.init(). A Postgres 15 service container is added to the generate-api-docs job — no migrations run, no tables required, just a live connection. Credentials are isolated to this job and do not affect other CI jobs.

Notes

• Output paths in export-spec.ts are anchored to __dirname, not cwd, so files always land at repo-root infrastructure/docs/ regardless of where the script is invoked from
• Spec metadata (title, description, version) matches main.ts
• app.listen() is never called — headless export only

[snowrugar-beep]

Smart move @temisan0x — exporting OpenAPI from CI means downstream tools and docs can stay in sync automatically. Thanks! ✅

[snowrugar-beep]

@temisan0x — heads-up: alongside the other merges that just landed in main, PR #76 now shows a content-level conflict in Backend/package-lock.json. To preserve your commit authorship cleanly, could you rebase PR #76 onto current main and push? Once it is conflict-free, I will merge immediately. Thanks for the OpenAPI artifact work! 🙏