feat(server): add swagger setup for public api documentation

Introduces Swagger and OpenAPI documentation generation for the
backend API. Configures bearer authentication globally while
allowing explicit bypasses for public endpoints. Exports nested
DTO classes across several modules so the NestJS Swagger plugin
can correctly reflect their schema definitions.

Closes #399

.gitignore

@@ -29,6 +29,7 @@ local/
 # Build artifacts
 coverage/
 *.tsbuildinfo
+server/src/metadata.ts
 
 # Test results (generated artifacts - uploaded to CI, not committed)
 test-results/