fix: apply Windows private ACLs to scan output directories

[batmnnn]

Summary

• Fixes Windows scan output directories are not ACL-hardened like credential homes #201: Windows scan output previously skipped all privacy checks (requirePrivateOutputDirectory / requireSecureOutputAncestry no-op on win32) while credential homes already applied a current-user-only ACL.
• Introduce requirePrivateScanOutput and a shared secureWindowsPrivateDirectory helper; apply + verify ACL on prepare and on every contract scan-root check.
• Enforce the same private-output gate for multiscan / bulk-scan campaign roots after mkdir.
• Add injectable Windows ACL unit coverage and a real-Windows ACL verification test (skipped on POSIX).

Test plan

• bun test --timeout 60000 ./tests-ts/runtime.test.ts ./tests-ts/contract.test.ts ./tests-ts/multiscan.test.ts ./tests-ts/bulk-scan-discovery.test.ts
• Injectable secureWindowsOutput is required for Windows scan-output privacy
• validatePreparedOutputDir invokes the Windows ACL hook
• On a Windows host: scan output ACL is protected + current-user-only (test included, skipped on POSIX CI)

[Copilot]

Pull request overview

This PR closes a security gap on Windows by ensuring scan output directories are protected with current-user-only ACLs (mirroring existing credential-home hardening), and by enforcing the same privacy gate across contract validation and bulk/multiscan flows.

Changes:

• Add requirePrivateScanOutput and refactor Windows ACL enforcement into a shared secureWindowsPrivateDirectory helper.
• Apply Windows scan-output ACL hardening during output preparation and during contract scan-root validation checks.
• Extend privacy enforcement to multiscan and bulk-scan output roots; add unit/integration test coverage (including a Windows-only ACL verification test).

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
sdk/typescript/src/runtime.ts	Introduces requirePrivateScanOutput and shared Windows private-ACL helper; wires scan-output validation to enforce privacy on Windows and POSIX.
sdk/typescript/src/contract.ts	Re-validates scan roots using requirePrivateScanOutput to ensure Windows scan directories are ACL-hardened during contract load/verification.
sdk/typescript/src/multiscan.ts	Ensures multiscan output directories are created and then privacy-validated (including Windows ACL enforcement via requirePrivateScanOutput).
sdk/typescript/src/bulk-scan-discovery.ts	Applies the same privacy gate to bulk-scan wizard output roots after creation.
sdk/typescript/tests-ts/runtime.test.ts	Adds injectable Windows-ACL hook coverage plus a Windows-only integration test verifying ACL protection/current-user-only access.
sdk/typescript/tests-ts/multiscan.test.ts	Adjusts test directory setup to satisfy stricter privacy requirements for multiscan output roots.

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[batmnnn]

Addressed the Copilot review notes:

• chmod now keys off the directory’s actual mode (mode & 0o077), not umask
• re-lstat after chmod so requirePrivateScanOutput sees current metadata
• clearer error when the path exists but is not a non-symlink directory

[mldangelo-oai]

@codex review Please review exact contributor-updated head 55b9aac, focusing on verified Windows output ACLs, actual POSIX directory modes, revalidated metadata, symlink/non-directory paths, and the failing Prettier checks in src/runtime.ts, src/multiscan.ts, and src/bulk-scan-discovery.ts.

[chatgpt-codex-connector]

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Reviewed commit: 55b9aac385

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[chatgpt-codex-connector]

Security review completed. No security issues were found in this pull request.

Reviewed commit: 55b9aac385

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[batmnnn]

Addressed the Codex review on 55b9aac:

• Ran Prettier on runtime.ts, multiscan.ts, and bulk-scan-discovery.ts
• POSIX mode normalization now requires exact 0700 (mode & 0o777), not only clearing group/world bits
• After Windows ACL apply/verify, re-lstat and bind the canonical path to the original dev/ino (rejects replacement mid-hardening)
• Added a regression for directory replacement during the Windows ACL hook

Focused suite: runtime, contract, multiscan, bulk-scan-discovery — all passing.

[batmnnn]

@mldangelo-oai can you take a look over this again please, thanks.