[Bug]: native Windows --write-worktree scoped observation rejects every in-scope path #7805

Impact

Native Windows users cannot acquire the documented --write-worktree hard lease for isolated code edits. On current main (70f643153ea773b7bc1ef71bdb06095b0744bd6d), any existing file or directory that matches the requested write scope is classified as a redirected path, so loopx task-lease acquire --write-worktree ... fails before creating the lease. New canonical Goals default to hard_lease, and the canonical lease guide recommends --write-worktree for independent worktree edits, so this blocks a primary multi-Agent editing workflow on Windows rather than an optional edge path.

This is a follow-up to #6653: that change supplied Windows machine identity, but scoped observation still fails before it can use that identity. It is not the same failure as closed #6640.

Minimal reproduction

Prerequisites: native Windows, Node.js with TypeScript stripping, and an independent Git worktree whose scope contains at least one existing entry.

From the root of such a worktree:

node --no-warnings --experimental-strip-types --input-type=module -e "import {observeLeaseWorktree} from './loopx/control_plane/work_items/task_lease_workspace.ts'; try { console.log(await observeLeaseWorktree(process.cwd(), p => p.startsWith('docs/'))); } catch(e) { console.error(e.name + ': ' + e.message); process.exitCode = 1; }"

Observed:

LeaseWorktreeObservationError: worktree scope contains a redirected path

The underlying path comparison also reproduces directly:

node --no-warnings --experimental-strip-types --input-type=module -e "import {realpath} from 'node:fs/promises'; import {join} from 'node:path'; const root=await realpath(process.cwd()); const full=await realpath(join(root,'docs')); console.log(JSON.stringify({root,full,prefix:root+'/',startsWith:full.startsWith(root+'/')},null,2));"

Observed with a synthetic checkout under C:\work\loopx-worktree:

{
  "root": "C:\\work\\loopx-worktree",
  "full": "C:\\work\\loopx-worktree\\docs",
  "prefix": "C:\\work\\loopx-worktree/",
  "startsWith": false
}

The write-scope oracle itself correctly reports the scope as overlapping:

{"overlap":true}
{"overlap":true}

Expected behavior

A regular directory or file physically inside the verified worktree must be accepted, including on Windows. Only an actual redirect outside the worktree (or a disallowed link) should raise worktree scope contains a redirected path. The observation should return the same path-free host/common-directory/worktree/repository identity used on macOS and Linux.

Actual behavior

At loopx/control_plane/work_items/task_lease_workspace.ts:130, the check compares:

!(await realpath(full)).startsWith(`${root}/`)

On Windows, realpath() returns a backslash-separated absolute path while the prefix is slash-terminated. The comparison is false for every child path. Once at least one scoped entry exists, every --write-worktree observation fails, even when no symlink, junction, or redirect exists.

The existing cross-platform observation test passes () => false as the overlap predicate, so it never enters this branch; the link test that does exercise scoped traversal is skipped on Windows.

Why this meets the importance bar

• Affected users and scale: every native-Windows user of the recommended independent-worktree code-edit flow; hard leases are the default for new canonical Goals, so the affected path is a normal multi-Agent workflow.
• Consequence: lease acquisition is deterministically blocked; agents must either abandon isolation or omit the documented flag, losing the checked checkout identity and overlap advisories.
• Persistence: the failure exists in the shipped source today and is not a transient environment issue; all Windows test lanes miss it because the scoped-observation branch is not exercised there.
• Actionable evidence: the minimal reproduction above fails on the exact baseline commit and the masked comparison is visible in the shared observation owner.

Environment

• LoopX commit: 70f643153ea773b7bc1ef71bdb06095b0744bd6d
• OS: native Windows 11 (Microsoft Windows NT 10.0.26200.0)
• Node.js: v26.11.1
• Git: 2.49.0.windows.1
• Host surface: Codex CLI / canonical task-lease command

Additional context

The unrelated Unicode case-folding/glob overlap work recently merged in #7243/#7252/#7786 is not involved. This report is about native path normalization in worktree observation.

AI disclosure: this issue was prepared with AI assistance and the reproduction was executed in a real native-Windows checkout.