test: make workspace history fixtures independent of Git identity

Write fixed commit objects from the fixture index rather than invoking
Git commit with an implicit machine identity. Preserve real history,
rename diff, pagination and dirty branch-switch checks without changing
Git author or committer configuration or skipping any affected test.

Add fixture checks for valid objects, parent linkage, unchanged dirty
content and unchanged repository configuration. Record the CI regression
introduced when the prior test identity override was removed.

Validation: workspace tests passed 11 with 2 filesystem skips; release
notes verification, typecheck and lint passed. Full tests passed 3845 with
66 skipped and one unrelated ActivityPanel timeout; all 16 ActivityPanel
tests passed on isolated rerun. Product source and approved bilingual
Desktop 0.12.11 / Agent 0.11.23 release notes are unchanged.

src/main/workspace/workspace-management.test.ts

@@ -16,6 +16,42 @@ async function repository(): Promise<string> {
 function git(root: string, ...args: string[]): string {
   return execFileSync('git', ['-C', root, ...args], { encoding: 'utf8', windowsHide: true }).trim()
 }
+function commitFixture(root: string, subject: string): string {
+  const tree = git(root, 'write-tree')
+  const branch = git(root, 'symbolic-ref', 'HEAD')
+  const parent = git(root, 'for-each-ref', '--format=%(objectname)', branch)
+  // Fixed object data, not a Git identity override: these tests read history
+  // and switch branches, and do not exercise Git's commit authoring command.
+  const input = [
+    `tree ${tree}`,
+    ...(parent ? [`parent ${parent}`] : []),
+    'author Workspace Test <workspace@example.invalid> 1788998400 +0000',
+    'committer Workspace Test <workspace@example.invalid> 1788998400 +0000',
+    '',
+    subject,
+    ''
+  ].join('\n')
+  const oid = execFileSync('git', ['-C', root, 'hash-object', '-t', 'commit', '-w', '--stdin'], {
+    input, encoding: 'utf8', windowsHide: true
+  }).trim()
+  git(root, 'update-ref', 'HEAD', oid)
+  return oid
+}
+it('creates valid fixture history without changing repository configuration or staging dirty content', async () => {
+  const root = await repository()
+  const configuration = await readFile(join(root, '.git/config'), 'utf8')
+  await writeFile(join(root, 'test.txt'), 'staged\n')
+  git(root, 'add', '.')
+  const first = commitFixture(root, 'initial')
+  await writeFile(join(root, 'test.txt'), 'dirty\n')
+  const second = commitFixture(root, 'empty')
+  expect(git(root, 'rev-parse', `${second}^`)).toBe(first)
+  expect(git(root, 'show', `${second}:test.txt`)).toBe('staged')
+  expect(await readFile(join(root, 'test.txt'), 'utf8')).toBe('dirty\n')
+  expect(git(root, 'log', '-1', '--format=%an')).toBe('Workspace Test')
+  expect(git(root, 'fsck', '--strict')).toBe('')
+  expect(await readFile(join(root, '.git/config'), 'utf8')).toBe(configuration)
+})
 it('creates, moves, inspects and deletes without overwriting an existing file', async () => {
   const root = await repository()
   await manageWorkspace(root, { kind: 'createDirectory', path: 'docs' })
@@ -33,9 +69,9 @@ it('reads unborn history, initial commit files and literal paths, and switches w
   await expect(manageWorkspace(root, { kind: 'history', offset: 0 })).resolves.toMatchObject({ commits: [] })
   await writeFile(join(root, '[test].txt'), 'initial\n')
   git(root, 'add', '.')
-  git(root, 'commit', '-m', 'Initial subject')
+  commitFixture(root, 'Initial subject')
   const oid = git(root, 'rev-parse', 'HEAD')
-  await expect(manageWorkspace(root, { kind: 'history', offset: 0 })).resolves.toMatchObject({ head: oid, commits: [{ subject: 'Initial subject', author: git(root, 'log', '-1', '--format=%an') }] })
+  await expect(manageWorkspace(root, { kind: 'history', offset: 0 })).resolves.toMatchObject({ head: oid, commits: [{ subject: 'Initial subject', author: 'Workspace Test' }] })
   await expect(manageWorkspace(root, { kind: 'commitFiles', oid })).resolves.toMatchObject({ files: [{ path: '[test].txt', status: 'A' }] })
   await expect(manageWorkspace(root, { kind: 'commitDiff', oid, path: '[test].txt' })).resolves.toMatchObject({ patch: expect.stringContaining('+initial') })
   await writeFile(join(root, '[test].txt'), 'dirty\n')
@@ -48,15 +84,15 @@ it('reads unborn history, initial commit files and literal paths, and switches w
 it('reports switch conflicts without discarding dirty content and pages stable history', async () => {
   const root = await repository()
   await writeFile(join(root, 'test.txt'), 'initial')
-  git(root, 'add', '.'); git(root, 'commit', '-m', 'initial')
+  git(root, 'add', '.'); commitFixture(root, 'initial')
   git(root, 'switch', '-c', 'other')
   await writeFile(join(root, 'test.txt'), 'other')
-  git(root, 'commit', '-am', 'other')
+  git(root, 'add', '.'); commitFixture(root, 'other')
   git(root, 'switch', 'main')
   await writeFile(join(root, 'test.txt'), 'dirty')
   await expect(manageWorkspace(root, { kind: 'switchBranch', branch: 'other', remote: false })).rejects.toThrow(/overwritten/)
   expect(await readFile(join(root, 'test.txt'), 'utf8')).toBe('dirty')
-  for (let index = 0; index < 51; index++) git(root, 'commit', '--allow-empty', '-m', `page ${index}`)
+  for (let index = 0; index < 51; index++) commitFixture(root, `page ${index}`)
   const first = await manageWorkspace(root, { kind: 'history', offset: 0 })
   expect(first.kind).toBe('history')
   if (first.kind !== 'history') return
@@ -73,11 +109,11 @@ it.each([false, true])('preserves rename metadata and actual edits in a literal
   const original = Array.from({ length: 20 }, (_, index) => `original line ${index}\n`).join('')
   await writeFile(join(root, previousPath), original)
   await writeFile(join(root, 'unrelated.txt'), 'unrelated before\n')
-  git(root, 'add', '.'); git(root, 'commit', '-m', 'before rename')
+  git(root, 'add', '.'); commitFixture(root, 'before rename')
   await rename(join(root, previousPath), join(root, path))
   if (edited) await writeFile(join(root, path), original.replace('original line 10\n', 'edited line 10\n'))
   await writeFile(join(root, 'unrelated.txt'), 'unrelated after\n')
-  git(root, 'add', '.'); git(root, 'commit', '-m', 'rename')
+  git(root, 'add', '.'); commitFixture(root, 'rename')
   const oid = git(root, 'rev-parse', 'HEAD')
   const files = await manageWorkspace(root, { kind: 'commitFiles', oid })
   expect(files).toMatchObject({ files: expect.arrayContaining([{ path, previousPath, status: edited ? expect.stringMatching(/^R\d+$/) : 'R100' }]) })