Connect and manage repositories

The Repositories tab connects each app to its GitHub repository. That connection powers three things: the nightly feature sync from the repo's docs, the repo context that AI task sessions read, and pull-request auto-import.

• Set the repository, branch, and context files for each project.
• Add a webhook secret to enable PR auto-import — merged members' PRs become pending activities automatically.
• Feature lists refresh on a daily schedule from each app's docs.