Address PR review (CodeRabbit + Augment): find_unpinned_stack scanned raw
body, so pipe-rows or ## headings inside a fenced block could be misread as
live Stack content and misreport version_pin. Now blanks fences first, like
find_placeholders and find_ad_issues, honoring the linter's fences-are-non-live
contract.
Also locate both Name and Version columns from the header (a reordered table
now pairs name to version correctly) and match the heading on a word boundary
(## Stack & Versions still counts). Add regression tests for fenced rows,
fenced headings, renamed heading, and reordered columns (28 passing).
Reword stale 'unpinned deps' / 'unpinned dependency versions' to 'unpinned
Stack versions' to match the body-table model.
237087ea03