/verified command not picked up from PR review comments

[damdo]

Bug

/verified by <name> (and other /verified subcommands) are silently ignored when posted as part of a Pull Request Review (i.e. when submitting a review with a body), but work correctly when posted as a regular issue comment.

Reproducer

1. On a PR, click Review changes, type /verified by ci in the review body, and submit.
2. The /verified label is not applied.
3. Post /verified by ci as a regular PR comment.
4. The label is applied.

Real-world example:

• PR review ignored: [release-4.19] OCPBUGS-80412: Bump google.golang.org/grpc to v1.79.3 openshift/cluster-api-operator#76 (review)
• Issue comment worked: [release-4.19] OCPBUGS-80412: Bump google.golang.org/grpc to v1.79.3 openshift/cluster-api-operator#76 (comment)

Root Cause

The plugin only registers handlers for IssueCommentEvent and PullRequestEvent in main.go:

eventServer.RegisterHandleIssueCommentEvent(serv.handleIssueComments)
eventServer.RegisterHandlePullRequestEvent(serv.handlePullRequest)

There is no handler registered for PullRequestReviewEvent, even though the githubeventserver framework fully supports it via RegisterReviewEventHandler.

When GitHub receives a PR review submission, it sends a pull_request_review webhook — not an issue_comment webhook. Since the plugin has no handler for that event type, the review body is never parsed for /verified commands.

Other Prow-native commands like /lgtm and /approve work from review bodies because those plugins have their own ReviewEvent handlers.

Proposed Fix

Add a handleReviewEvent method to server.go that extracts the review body, splits it into lines, and processes /verified commands the same way digestComment/digestLine already do for issue comments. Then register it in main.go:

eventServer.RegisterReviewEventHandler(serv.handleReviewEvent)

/cc @damdo