Resolve and rereview PR comments republish the whole history and are unreadable; show only the round's delta #475

Problem

Resolve and rereview comments on a PR are unreadable. Each round republishes the whole accumulated history instead of what changed. On PR #468 (issue #439), one resolve comment has:

• 23 receipt header lines (CCR-…/CCT-…), one per stage ever run, when only the latest receipt matters.
• A full entry for each of 16 unchanged findings (REV-001–REV-016), each ending in "No change. … passes at the new head."
• Paragraphs of implementation narrative per fixed finding (function names, regex details, membership rules) that duplicate the diff and commit messages.
• A long defence of a finding the runtime marked contested.
• Fixed sections repeated every round even when nothing changed: post-change review, security, docs, verification table, environment, CI, residual risk.

The information that changed in that round fits in about five lines: two findings fixed with tests, one contested finding confirmed resolved, verification not_verified because of AC-8, CI pending.

Expected

A comment a human can read in under a minute, with full evidence still available.

Acceptance criteria

• AC-1: The visible part of a resolve or rereview comment shows only the delta of the round: findings whose status, disposition or evidence changed in this round, each with one line for cause, fix and test.
• AC-2: Unchanged findings are collapsed into a single count line (for example REV-001–016: unchanged, regression check passes).
• AC-3: Receipt headers, the verification table, environment and full per-finding history go inside a collapsed <details> block; only the latest receipt header is visible.
• AC-4: A section with no change since the previous round is reduced to one line (Security: no change) or omitted.
• AC-5: The structured data the runtime parses (receipts, finding IDs, dispositions) is preserved and still parsed correctly; existing receipt and finding-recovery tests pass, with a regression test on a multi-round comment.
• AC-6: The comment templates in cc-resolve-comments, cc-rereview and cc-initial-review (shared sections kept in sync) and the owning docs/ page describe the new layout.
• AC-7: A length budget for the visible part of a comment is defined and checked by a test.