fix(ci): release CI ownership on deferred-green to break rework deadlock

[chihsuan]

Context

CiPoller and PrReviewPoller can deadlock: after a rework, a green CI check that is deferred keeps its failure-owned status/retry count, so neither poller ever advances the PR's pending reviewer comments.

TL;DR

Green-but-deferred CI now relinquishes failure ownership so the review poller can dispatch the pending rework.

Summary

• mark_ci_green deferred branch now resets ci_retry_count/failed_checks/ci_failure and drops owned statuses to watching.
• Add released_deferred_status/1 so a green check no longer satisfies ci_owned_record?/1 while finalize stays deferred.
• Update CI poller tests to expect ownership release on deferred-green; assert ci_owned_issue?/2 returns false.

Alternatives

• Guard ci_owned_record?/1 on last_action == "green_deferred": couples the reader to a log string and leaves stale owned state on the record.
• Exempt green from ci_owned_issue?/2 in the review poller: fixes one caller but keeps the misleading persisted state.

Test Plan

• make all
• mix test test/symphony_elixir/ci_poller_test.exs test/symphony_elixir/pr_review_poller_test.exs
• mix format --check-formatted, mix specs.check, mix credo