pr: https://git.cafe/pingdotgg/t3code/pulls/23184 (github 23167)
main: 4c924ff4e6d0828e0a5810336ec7d7827d752645
original head: 59e4b3f34bceb8c74d0ea059c7e3df671c3f2848
fixed head: a0373688ab236c65e310ab6519d36034739b3453

environment: linux, repository Playwright 1.60.0, /usr/bin/google-chrome.
provider: real Codex gpt-6.1-sol through the web composer and local proxy.
no mocks, fixtures, replay provider, or direct database writes.

setup:
git worktree add ../main github/main
cd ../main && vp i
setsid nohup vp run dev --no-seed > /tmp/main-dev.log 2>&1 &
captured main process group 19100, ports 8693/16733.
created local git project through Add project > New project.
real Codex turn created and committed back\slash.txt, back/slash.txt, plain.txt.
second real turn appended 1, 2, 1 lines, respectively, without committing.

main observed:
changes card: back folder +3, two slash.txt rows (+2 and +1), plain.txt +1.
clicked +1 slash.txt row: expanded back/slash.txt, showing BASE_NESTED.
clicked back\slash.txt in diff header: file viewer opened BASE_NESTED.

stopped captured main process group before starting candidate.
copied only task-created isolated userdata to candidate .t3 for matching data.
candidate runs with explicit --home-dir /home/user/t3code/.t3.
candidate ports: 5733 web, 13773 server. only one dev server at a time.

original head observed:
changes card: back folder +2, independent back\slash.txt +1, plain.txt +1.
literal row expands back\slash.txt diff, showing BASE_LITERAL and LITERAL_ADDED.
literal diff header opens BASE_LITERAL in file viewer.
nested and plain rows each open the correct diff and file content.
collapse-all hides nested slash.txt but preserves literal root row.
expand-all restores nested slash.txt.
new real candidate Codex turn appended PR_LITERAL_ONLY only to literal file:
one-file card, exact literal name, no expand/collapse-all folder control.
context Open RPC: cwd ends /back\slash.txt, editor=file-manager.
context Reveal RPC: same exact cwd, reveal=true.
observed linux Files select back\slash.txt (43 bytes).

additional real project scenario:
Codex created nested\workspace/a.ts and committed the baseline.
added nested\workspace as another local project through the app.
real Codex turn appended NESTED_WORKSPACE_ADDED to a.ts.
original head header click attempted:
  /repo/nested\workspace/nested\workspace/a.ts
file viewer displayed inaccessible-file error.
repository had no remote, so project repositoryIdentity was null.

fix:
DiffPanel uses existing live git-status workingTree.rootPath.
changes-card context menu reads the same shared status root, selecting only root.
existing browser test file extended with a nested-project/no-remote regression.

blacksmith regression before fix:
expected activeSurfaceId file:back\slash.txt
received activeSurfaceId file:project/back\slash.txt
1 failed.

after fix:
nested header opens a.ts with NESTED_WORKSPACE_BASE and NESTED_WORKSPACE_ADDED.
context Open and Reveal both send exact /repo/nested\workspace/a.ts.
reinstalled dependencies and restarted candidate using captured own process group.
another real Codex turn appended export const restarted = true; to a.ts.
clicked new turn's row and header; file viewer showed all three lines.

blacksmith final head:
vp run check:changed
pass format, lint, knip 1/2, knip 2/2, typecheck (2 packages),
test (3 files: 29 passed), react compiler (5 files).
no new test files created.

evidence:
matching main/candidate screenshots inspected at full size.
matching nested failure/fix screenshots inspected at full size.
16.2s recording inspected; loading gaps trimmed, playback speed unchanged.
uploaded video played to completion and seeking checked in Chrome and T3 preview.

not exercised:
native Electron, iOS, Android, Windows/macOS hosts, relay/tunnel connections,
other providers. file viewer tab/breadcrumb label still splits literal backslashes;
content and resolved file path are correct. this existing label issue is unchanged.