Avoid redirected USERPROFILE daemon trap

[coneilen]

Summary

Prevents graphcoded.exe from trapping when USERPROFILE is redirected by handling an empty Foundation application-support lookup. Fixes #558.

Changes

• Fall back to the configured default support directory when Foundation returns no legacy application-support directory.
• Add injected Windows and macOS unit coverage for the empty lookup.
• Add a production direct-process regression that redirects only USERPROFILE, uses explicit owned support and temp directories, and verifies clean startup and shutdown.

Test plan

RED: pwsh -NoProfile -File Tools\windows\Tests\RedirectedUserProfileDaemon.Tests.ps1 -DaemonExecutable .build\issue-558\release\graphcoded.exe -ScratchRoot .build\issue-558\red -> graphcoded.exe shutdown returned 0xC000001D
GREEN: pwsh -NoProfile -File Tools\windows\Tests\RedirectedUserProfileDaemon.Tests.ps1 -DaemonExecutable .build\x86_64-unknown-windows-msvc\release\graphcoded.exe -ScratchRoot C:\gc-issue-558\final-green -> redirected profile daemon passed with exit 0x00000000
REGRESSION: pwsh -NoProfile -File Tools\windows\validate.ps1 -Task swift-production -SwiftExecutable C:\Users\coneilen\AppData\Local\Programs\Swift\Toolchains\6.3.3+Asserts\usr\bin\swift.exe -> 101 XCTest and 6 Swift Testing cases, release builds, direct-process regression, and clean runtime smoke passed

pwsh -NoProfile -File Tools\windows\validate.ps1 -Task swift-format -SwiftExecutable C:\Users\coneilen\AppData\Local\Programs\Swift\Toolchains\6.3.3+Asserts\usr\bin\swift.exe passed.

The shared macOS path was not executed locally on Windows. Exact-head macOS shared CI is required before merge.

Checklist

• I have read the Contributing Guidelines
• I have signed off my commits (git commit -s) per the DCO
• Tests pass locally (make test)
• Code follows the existing style (make check)
• I added the test/contract before the implementation and observed the intended RED failure