feat: support multiple URLs for GET endpoint (issue #187)

[mesiyoq965-sudo]

Summary

Support multiple issue URLs for the GET /start endpoint, as requested in issue ubiquity-os-marketplace#187.

Changes

1. Add optional issueUrls array parameter alongside the existing issueUrl parameter
2. Add handleMultiUrlValidateOrExecute to process multiple URLs sequentially and return results as a batch
3. Add MultiUrlResult type for the batch response structure
4. Modify public-api.ts to route to the multi-URL handler when issueUrls is present
5. Maintain backward compatibility with single issueUrl parameter

API Usage

Single URL (existing behavior):

GET /start?userId=123&issueUrl=https://github.com/owner/repo/issues/1

Multiple URLs (new):

GET /start?userId=123&issueUrls=https://github.com/owner/repo/issues/1&issueUrls=https://github.com/owner/repo/issues/2

Response for multiple URLs:

{
  "results": [
    { "issueUrl": "...", "ok": true, "computed": {...} },
    { "issueUrl": "...", "ok": false, "reasons": ["..."] }
  ]
}

Motivation

This allows devpool-directory and daemon-planner to check hundreds of tasks in a single request, avoiding rate limits when checking multiple tasks sequentially.

Testing

Tests updated to cover both single and multi-URL scenarios.

Related

• Closes Allow multiple URLs for the GET endpoint ubiquity-os-marketplace/command-start-stop#187