An operator's merge on the forge deploys a config PR through
swarm-controller's DeployRequest{rev}. The hive-side path that queued a
MergeConfigPr approval and merged the PR as `core` goes:
- the `/webhook/config-pr` receiver, its HMAC secret, the WebhookRegister
boot node and the org-hook registration; the hive vhost's `/webhook/`
location
- the 5-minute config-PR poll
- ApprovalKind::MergeConfigPr, its dashboard card, and the deploy DAG it
drove (DeployWindow, MergeVerify, DeployApply, FinalizeDeploy,
DeployTail), with verify_commit, the two-phase meta deploy, rollback
refs, the PR-failure comment and forge/pr_merge.rs
- `fetched_sha`, `sha_short`/`pr_number` on approval events, and
`sha`/`tag` on HelperEvent::ApprovalResolved: only the merge path set
them
`config_repo`, `merged_pr_for_commit` and `post_pr_comment` move to
forge/pr_comment.rs for the merged-rev deploy's refusal comment.
Approvals v5 drops stored `merge_config_pr` rows; a test reopens a v4
database holding them.
Closes#4850