[mforce]

Closes #1342

Why

In a linked worktree, the pre-commit hook exports GIT_DIR without GIT_WORK_TREE. TenancyDocsFreshnessTests.RepoRoot() ran git rev-parse --show-toplevel from the test's bin folder, so git returned that bin folder. FileSizeLimitTests and SpellingScannerRatchetTests then threw DirectoryNotFoundException, and commits in worktrees fell back to --no-verify.

The issue says all three tests failed. TenancyDocsFreshnessTests passed. It skips paths that are missing on disk, so it read 0 files and found nothing to flag.

What changed

One test file, tests/Cluckwork.Application.Tests/Documentation/TenancyDocsFreshnessTests.cs:

• RepoRoot() uses GuardScanner.FindRepoRoot, the same as RenameAccountDocsTests.RepoRoot().
• The tenancy wording walk fails when it reads 1,000 files or fewer, so a wrong root can no longer pass silently. It read 2,561 on 2026-10-21. The floor assumes a full checkout, as CI uses; a sparse checkout below 1,000 files would fail it.
• The new TenancyDocsFreshnessRepoRootTests sets GIT_DIR to the checkout's real git dir and asserts that the returned root holds Cluckwork.slnx. The existing RenameAccountDocsRepoRootTests covers only the other helper.

Verification

• dotnet build Cluckwork.slnx reports 0 warnings. The filtered tests (TenancyDocsFreshness, FileSizeLimitTests, SpellingScannerRatchetTests, RenameAccountDocsRepoRootTests) pass 7/7, both normally and with GIT_DIR set to the worktree's git dir.
• With the old helper restored and GIT_DIR exported to the worktree's git dir, FileSizeLimitTests and SpellingScannerRatchetTests throw DirectoryNotFoundException under bin/Debug/net10.0/, and the tenancy walk fails with Read only 0 tracked files under .../bin/Debug/net10.0. Before the floor, the tenancy walk passed in this setup.
• With the old helper restored and no GIT_DIR exported, the new test sets GIT_DIR itself and fails with RepoRoot() returned .../bin/Debug/net10.0.
• A first version of the new test asserted on the git ls-files output. It stayed green against the old helper, because ls-files lists the whole index even when git takes bin as the work tree. The test now checks the file on disk instead.
• Both commits went through the pre-commit hook in a linked worktree without --no-verify (Domain 496/496, Application 783/783).