Point the public site to each project's TaskStream board

A project with a board now carries its key, its address and the address
of the board's public showcase in the public API, so the website can show
its roadmap, releases and tickets for newcomers.

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

public/openapi.yaml

@@ -5041,6 +5041,15 @@ components:
         repositories:
           type: array
           items: { $ref: "#/components/schemas/PublicRepository" }
+        taskstream:
+          type: object
+          nullable: true
+          description: "Its board in TaskStream, if it has one. `showcase_url` answers without a token: roadmap, releases, the sprint under way and tickets labelled good-first-issue."
+          properties:
+            key: { type: string, example: WEB }
+            url: { type: string, format: uri }
+            web_url: { type: string, format: uri }
+            showcase_url: { type: string, format: uri }
         alternates: { $ref: "#/components/schemas/Alternates" }
         path: { type: string, nullable: true, example: /proyectos/mi-web }