fix(pm): judge a review of record's Served-tier line on every pair that has one

`check-clause2-carriers --pair` read the `Served-tier:` provenance line only
beside a gate clear: `reviewOfRecord` answered `not-owed` before any thread was
read unless the pair was in C6's completed state, so C7 — the row that carries
`references/contract-review.md`'s 「无此行不成裁决」 — was consulted on one path
of two. Measured on one board in one day, one spelling: record 5661052272
(PR #18157 / card #17991, non-gated) carried a `Served-tier:` line this file's
own reader answers `unreadable` for and `--pair` exited 0, while the same
spelling on objectui PR #9486 was refused exit 4, because that pair's gate had
been hung and cleared.

Split the reader in two: `locateReviewOfRecord` finds the record on the head
with no reference to the gate, and `reviewOfRecord` is that locator under C6's
population gate. C7 and the C6-RECORD note read the locator; C6's row, its
「not-owed」 scope, the accept set, the exactness and the remedy are unmoved.
The `--pair` path buys the PR thread for every pair (`landingReads`), the sweep
does not, and `locatedRecordUnjudged` is the landing path's own #4690 half so an
unread thread is UNJUDGED rather than clean.

Claude-Session: https://claude.ai/code/session_01HZfg2AwVX191qCizp88gQr
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude