Add the experimental forge capability seam:
- dsh-experimental-forge: provider-neutral repository and change request
references, a provider registry, and shared status polling. Watchers of
one change request share one loop; each forge has one batched fetch in
flight, and the cadence follows check, mergeability, and lifecycle state.
- dsh-experimental-forge-github: GitHub provider that runs the GitHub CLI
on the host with a scrubbed environment and reads every due pull request
of a host in one GraphQL query.
- dsh-experimental-forge-session: a host-only projection derives Session
bindings from gh pr create and git push shell results and from
plugin:forge-session/binding records; push results trigger head-branch
discovery of open pull requests, and Session watchers poll bound change
requests through ctx.forge.
Yichen Jiang