v1.3.0: when the headline is a NULL, assert extraction completeness - #28

…ence your work survived it (1.4.0) (#29)

Adds "Pre-flight: stale-base audit — what your OWN branch deletes", placed
immediately after the parallel-branch file-collision audit as its inward mirror.
That audit looks outward at branches that might conflict with you; this one looks
at the branch you are about to merge.

THE EVIDENCE IS ONE INCIDENT, 2026-08-07. A pull request merged from a branch
created before several other pull requests landed and never rebased; its conflict
resolution took its own side across the whole tree. 59 files, 1,891 insertions,
5,081 deletions. It reverted 11 files and 15 tracker entries belonging to three
other sessions -- source modules, their tests, analysis pages, handoff prompts,
tracker rows -- plus a function two surviving files still imported. Nothing
failed: no conflict, green PR, schema validator passed, site still rendered. All
three sessions had finished a wrap-up that morning and their work WAS on main,
for between 6 and 90 minutes. The merged content was legitimate and had to stand,
so git revert was the wrong tool.

TWO DOTS, NOT THREE -- a correction the drafting turned up. The brief for this
change proposed `git diff origin/main...HEAD --diff-filter=D`. Three dots diffs
from the MERGE BASE, so on a branch that never took main's newer commits a file
added to main after the branch point is absent from both sides and reports as no
change at all. Verified on a two-commit synthetic repo: three-dot prints nothing,
two-dot prints the file. The section ships the two-dot form, rebase-first
ordering, and the note that a plain merge of a stale branch is harmless -- the
damage needs the branch's tree to win wholesale.

THE EXISTENCE CHECK IS THE WEAK ONE. `git cat-file -e` asks only whether a path
exists; a file can be present with its contents rolled back and no existence
check, id check or validator will report it. Audit instead for a marker your
change ADDED. Worked example, measured rather than argued: a page of seven
interactive widgets whose option lists are single-quoted HTML attributes, three
holding an apostrophe behind a one-character `'`. Roll that escape back on
the fourth widget and the file exists, the HTML is valid, all seven widgets are
in the markup, every committed check passes -- and four of the seven are silently
dead, because the truncated attribute throws inside the one forEach that builds
them all. Loading the real page with each escape rolled back in turn gives three
working, or none if the first widget is the one broken.

Recovery is a splice-forward (`git show <sha>:<path>`), never a revert.

Version: SKILL frontmatter, plugin.json and marketplace.json all 1.3.1 -> 1.4.0.
Bundle VERSION already reads 1.4.0 from the 2026-08-06 release and is unchanged:
it is the bundle's own counter, not a mirror of this plugin's version, and the
release one day earlier (#28) shipped a plugin bump without touching it.

Gates: check_skill_descriptions --triggers exit 0 (description byte-identical,
1,463 chars, 8 triggers unchanged per --compare); leak_scan clean;
validate_plugins OK, 0 warnings.


Claude-Session: https://claude.ai/code/session_01UCqwdBqETB9SeEVR2fSTfK

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>