review: drop redundant square banner + demote readiness chip on non-ready verdicts

[JSONbored]

Part of #6065.

Problem

renderUnifiedReviewComment (src/review/unified-comment.ts:656) prepends meta.square.repeat(12) -- a row of 12 repeated colored-square emoji -- before the headline. GitHub's own > [!CAUTION]/[!TIP]/etc. alert blockquote (asAlert, unified-comment.ts:612) already renders a colored left border + icon for the same status, so the square row duplicates that with no new information. It also reads as visual noise on an otherwise clean comment.

Separately, statusChips() (unified-comment.ts:394) always renders a readiness N/100 chip when ctx.readinessScore is a number, with no relation to status. The readiness score is advisory-only by design (see deriveUnifiedStatus's own comments, unified-comment.ts:339-343 -- it never feeds the gate). Showing e.g. "readiness 93/100" next to a "fixes required" / blocked verdict reads as contradictory to a reader who doesn't already know the score is advisory-only.

Proposed fix

• Remove the meta.square.repeat(12) banner line entirely; rely on the alert blockquote's own color+icon.
• Only render the readiness chip when status === "ready" (or otherwise make clear via label/placement that it's advisory and independent of the verdict) -- exact call left to implementation, but the chip must never appear to contradict the Suggested Action line.
• Give the "Suggested Action" verdict line (verdictLine(), unified-comment.ts:411) a visually distinct treatment (e.g. its own callout box) instead of a plain bold line in the body flow, since it's the single most load-bearing line in the comment.

Files

• src/review/unified-comment.ts
• test/unit/unified-comment.test.ts (or wherever its tests live -- update chip/banner assertions)

[linear-code]

JSO-4179