feat(api): REST API with OpenAPI for other apps, behind Pireon OAuth

A REST adapter next to GraphQL (presenters/http) that calls the same
application services, so validation, permissions and domain errors are the
same: projects (members, board, stats, activity), issues (search, workflow,
assignee, release, links, comments, history), comments, releases and users.
Projects and issues can be addressed by id or key (WEB, WEB-12).

- Swagger UI at /api/docs, document at /api/docs-json and apps/api/openapi.json
  (rewritten by `nx serve api`, like schema.gql) for client generation.
- Every route but health/auth/webhook needs a Pireon token: the document
  declares Pireon OAuth2 (authorization code + PKCE, password) through the
  /api/auth/token proxy, and a bearer scheme for apps with their own client.
- configureApp() shares main.ts setup with the e2e, which now also covers REST.
- SWAGGER_ENABLED / OPENAPI_FILE config; docs 03/05 and library READMEs.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/api/identity/presenters/src/lib/http/auth.controller.ts

@@ -6,6 +6,15 @@ import {
   Post,
   UnauthorizedException,
 } from '@nestjs/common';
+import {
+  ApiBody,
+  ApiConsumes,
+  ApiOkResponse,
+  ApiOperation,
+  ApiProperty,
+  ApiTags,
+  ApiUnauthorizedResponse,
+} from '@nestjs/swagger';
 import {
   IdentityService,
   InvalidCredentialsError,
@@ -18,10 +27,29 @@ import {
 import { Public } from '../auth/auth.decorators';
 import { IssueTokenDto } from './dto/issue-token.dto';
 
+export class AuthorizationConfigDto {
+  @ApiProperty({ example: 'https://oauth.pireon.dev/oauth/authorize' })
+  authorizeUrl!: string;
+  @ApiProperty({ description: 'Public id of the task-stream OAuth client' })
+  clientId!: string;
+  @ApiProperty({ type: [String], example: ['users:read'] })
+  scopes!: string[];
+  @ApiProperty({ description: 'Whether email + password sign-in is allowed' })
+  passwordGrant!: boolean;
+}
+
+export class TokenResponseDto {
+  @ApiProperty() access_token!: string;
+  @ApiProperty({ type: String, nullable: true }) refresh_token!: string | null;
+  @ApiProperty({ description: 'Seconds' }) expires_in!: number;
+  @ApiProperty({ example: 'Bearer' }) token_type!: string;
+}
+
 /**
  * Sign-in for browsers. Pireon's /oauth/token has no CORS and the client
  * secret must stay server-side, so the web app goes through here.
  */
+@ApiTags('Auth')
 @Controller('auth')
 export class AuthController {
   constructor(private readonly identity: IdentityService) {}
@@ -29,6 +57,10 @@ export class AuthController {
   /** What the web app needs to start Authorization Code + PKCE (null = not configured). */
   @Public()
   @Get('config')
+  @ApiOperation({
+    summary: 'How to sign in with Pireon (null when not configured)',
+  })
+  @ApiOkResponse({ type: AuthorizationConfigDto })
   config(): Promise<AuthorizationConfig | null> {
     return this.identity.authorizationConfig();
   }
@@ -36,6 +68,18 @@ export class AuthController {
   @Public()
   @Post('token')
   @HttpCode(200)
+  @ApiOperation({
+    summary:
+      'Exchange a grant for Pireon tokens (proxy of Pireon /oauth/token)',
+    description:
+      'For browsers (Pireon has no CORS) and Swagger UI: adds the client secret ' +
+      'server-side. Apps with their own Pireon OAuth client can get tokens from ' +
+      'Pireon directly; any valid Pireon access token is accepted by this API.',
+  })
+  @ApiConsumes('application/json', 'application/x-www-form-urlencoded')
+  @ApiBody({ type: IssueTokenDto })
+  @ApiOkResponse({ type: TokenResponseDto })
+  @ApiUnauthorizedResponse({ description: 'Pireon rejected the grant' })
   async token(@Body() dto: IssueTokenDto) {
     try {
       return toResponse(await this.identity.issueToken(toGrant(dto)));