repo-maintenance: treat CodeRabbit limit messages as non-blocking

[gaelic-ghost]

Summary

Adjust the repo-maintenance release/PR gates so CodeRabbit comments or statuses that say the review cannot produce useful information because limits/quota were hit are treated as terminal non-blocking signals, not as something the release script should wait on indefinitely.

Reference

Closest current reference from a SwiftASB release PR: gaelic-ghost/SwiftASB#85 (comment)

That example is a CodeRabbit in-progress/pending comment rather than the explicit quota-limit wording, but it shows the failure mode: repo-maintenance waited on a CodeRabbit status that was not yielding actionable review information. If we find a clearer CodeRabbit "limit reached" comment later, add it here as the canonical fixture/example.

Desired Behavior

• Detect CodeRabbit comments/check output that indicate quota, usage, or review limits were reached.
• Treat those as non-actionable review-unavailable states instead of blocking release progress.
• Keep real CodeRabbit findings, requested changes, or failed checks blocking.
• Prefer a small parser/helper with fixtures so repo-maintenance behavior is testable.

Notes

The practical rule is: if CodeRabbit is explicitly saying it cannot provide review information, there is no value in waiting for it as a review gate.