Tracking fws U8: diff-view save publishes through the guard #2427

Split-unit tracking note for the file-write-safety chain (#1375), filed 2026-11-11 for PR #1916, which is unit U8 of that split and carried no unit-level tracking issue when it opened on 2026-10-05T12:13Z.

Sibling units of this split are tracked at issues 2016 through 2021 and 2024; this note is written in the same shape and is the plan-of-record carrier for U8 from today forward. The plan post-dates the pull, which is what the campaign's planned-and-issued rule asks for and this chain did not have.

Unit

• Unit: U8 (branch fws/u8-diffview-guarded-save, PR feat(editor): route the diff-view save through the guard (U8, #1375) #1916).
• Head at the time this note was filed: da2b91316158ce2ac38f8df7243f7384b3518663. The head has not moved since the 2026-11-10T16:18Z measurement round that produced the figures below.
• Merge base recorded for this head: a0d03a06a3aff42e2e4561e881911e48ff3bff42.

What the pull changes

• 31 files changed, 13889 insertions(+), 338 deletions(-) at the merge-base delta.
• Largest contributors, in changed executable lines counted for the deciding package: src/integrations/editor/DiffViewProvider.ts 724 (over the 500 limit on its own), src/core/tools/guardedWrite.ts 460, src/services/file-safety/safeWriteText.ts 344.

Price, with the base named

• Against main tip 18861b2e357203e6cb4d93930aa2ed122b1eecea merged with this head (the CI-shaped candidate), the deciding package extension has 1797 changed executable lines against the gate limit of 500.
• Against this branch's own merge base a0d03a06a3aff42e2e4561e881911e48ff3bff42, the same 1797: no other campaign head is an ancestor of this head, so the unit price and the merge-base price coincide.
• The base the pull's own CI used, main tip ba105e65cc74, gives the same 1797.

Mutation state

• The gate stops at the size check before any test or mutant run, so no mutation result exists for this unit at this head. Verbatim from the run: extension has 1797 changed executable lines (limit 500). Split the PR or obtain a maintainer-reviewed narrow exclusion..

Figures are from the lane's size-cap measurement round of 2026-11-10 (row 1916 of the published cap table), re-derived locally against refs/dsh-cap/pr/1916 rather than read off the pull page.