Open a TaskStream board when a project is created through the API

`taskstream: true` on POST /v1/projects also creates the project in
TaskStream, public, as the caller (their Pireon token is passed on), and
the answer carries `taskstream_key` and `taskstream_url`. The key is
`taskstream_key` or one made from the default-language slug.

The board is opened before the project is saved: if TaskStream refuses
it, nothing is created here and the reason comes back as a validation
error (502 when TaskStream does not answer). Machine tokens need the
server's own TASKSTREAM_TOKEN. Updates ignore the flag, and duplicates do
not inherit the link.

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

public/openapi.yaml

@@ -1566,6 +1566,16 @@ paths:
         `technology_ids`, `service_ids`, and `members` with each one's role.
         `published_at` and `unpublish_at` require `projects.publish`. For a
         cover, upload it with `POST /v1/media` and `for: projects`.
+
+        With `taskstream: true` the project also gets a **public** board in
+        TaskStream, the collective's issue tracker, and the answer carries its
+        link in `taskstream_url`. Its key is `taskstream_key`, or one made from
+        the slug in the default language (one word: its first ten characters;
+        several: their initials). The board is opened first: if TaskStream
+        refuses it (a key in use, say), nothing is created here either and the
+        reason comes back as a validation error. It is opened as the caller,
+        whose Pireon token is passed on; a machine token cannot ask for one
+        unless the server has a `TASKSTREAM_TOKEN` of its own.
       requestBody:
         required: true
         content:
@@ -1582,6 +1592,8 @@ paths:
                   data: { $ref: "#/components/schemas/Project" }
         "403": { $ref: "#/components/responses/Forbidden" }
         "422": { $ref: "#/components/responses/ValidationError" }
+        "502":
+          description: TaskStream did not answer; nothing was created.
 
   /v1/projects/{project}:
     parameters:
@@ -5503,6 +5515,8 @@ components:
         is_featured: { type: boolean }
         needs_help: { type: boolean }
         demo_url: { type: string, nullable: true, format: uri }
+        taskstream_key: { type: string, nullable: true, description: "The project's key in TaskStream, when it has a board there." }
+        taskstream_url: { type: string, nullable: true, format: uri, readOnly: true, description: Where its TaskStream board opens. }
         cover_image: { type: string, nullable: true, description: The stored path — what a client PATCHes back. }
         cover_image_media:
           allOf: [{ $ref: "#/components/schemas/Image" }]
@@ -5549,6 +5563,14 @@ components:
         is_featured: { type: boolean }
         needs_help: { type: boolean }
         demo_url: { type: string, format: uri, nullable: true }
+        taskstream:
+          type: boolean
+          description: On creation only. Also open a public board for it in TaskStream; see `POST /v1/projects`.
+        taskstream_key:
+          type: string
+          nullable: true
+          pattern: "^[A-Za-z][A-Za-z0-9]{1,9}$"
+          description: On creation only, with `taskstream`. The key in TaskStream; made from the slug when left out.
         cover_image: { type: string, nullable: true, description: A path from `POST /v1/media` with `for=projects`. }
         started_at: { type: string, format: date, nullable: true }
         ended_at: { type: string, format: date, nullable: true }