PR 29579: fbbb567c52a1d25dec1f189532df97230d6551c9
Baseline github/main: 30084f0018c5751a07291222e8d04e16d513700a
Linux VM; Google Chrome; Playwright from apps/web dependencies.
Project and threads created in the app. Real Codex gpt-6.1-sol turns created and committed the baseline, enabled local diff.suppressBlankEmpty=true, and edited the files.

$ git config --local --get diff.suppressBlankEmpty
true
$ nl -ba README.md
1  # blank context verification
2
3  after
4
5  tail

Main, actual client turn diff and Uncommitted view:
README.md lines: header=1, before=2, after=2, tail=3; blanks missing.
Browser: processFile: invalid rawLine
Browser: parsePatchContent: hunk line count mismatch; declared old/new 5/5, parsed old/new 3/3.

PR, fresh real Codex edit turn, actual client turn diff and Uncommitted view:
README.md lines: header=1, blank=2, before/after=3, blank=4, tail=5.
No invalid-rawLine or hunk-count errors.
plain.txt old/new=1; untracked.txt untracked=1.
Split and stacked views preserve correct numbering.
Click line 3 add-comment: editor label Comment on lines +3.
Submitted comment appears as README.md L3 in composer and user message.
Real Codex response: verified: README.md line 3 contains after. no files changed.
Local diff.suppressBlankEmpty remains true; persistent config was not changed by patch reads.

$ blacksmith-check run ... "cd apps/server && vp test run src/checkpointing/CheckpointStore.test.ts src/vcs/GitVcsDriverCore.test.ts src/vcs/GitVcsDriver.test.ts"
3 files passed, 300 tests passed.
$ blacksmith-check run ... "... && vp run check:changed FETCH_HEAD"
4 changed files against PR parent cbd3e149a130.
format PASS; lint PASS; knip 1/2 PASS; knip 2/2 PASS; graphql PASS; typecheck (3 packages) PASS; tests (4 files, 301 tests) PASS.

Not exercised: native desktop shell, iOS/Android, other providers, remote/relay connections, live branch-range and commit review selection. Existing VCS tests cover commit/branch review patch generation.
Incidental: a cold diff-worker load once logged unresolved pierre-dark theme; client rendering continued and line numbers were correct. No related parser errors on PR.