#17862: fix: Windows exec returns empty output when pty=false

## Summary On Windows, the exec tool returns empty output when pty=false (the default) when running via Scheduled Task. This is a regression introduced in the process supervisor refactoring (commit cd44a0d01). The root cause is that the new child adapter always uses detached: true, but on Windows, detached processes don't have proper console handles for stdout/stderr capture. ## Changes - Changed detached: true to detached: process.platform !== "win32" in src/process/supervisor/adapters/child.ts - This restores the previous behavior where Windows used detached: false ## Testing - All existing tests pass (20 supervisor tests, 5 exec tests, 3 bash-tools.exec tests) Fixes openclaw/openclaw#17806 <!-- greptile_comment --> <h3>Greptile Summary</h3> Fixes a Windows-specific regression where exec tool returns empty output when `pty=false`. The root cause was that `detached: true` (introduced in the supervisor refactoring at commit cd44a0d01) causes Windows child processes to lose their console handles, preventing stdout/stderr capture — especially when running via Scheduled Task. - Sets `detached: process.platform !== "win32"` so Windows uses `detached: false` while Unix/macOS retains `detached: true` (needed for process-group kill via `process.kill(-pid)`) - Conditionally removes the "no-detach" spawn fallback on Windows since it would be redundant when already non-detached - Process cleanup is unaffected: Windows `killProcessTree` uses `taskkill /T /PID` which works regardless of detach mode <h3>Confidence Score: 5/5</h3> - This PR is safe to merge — it is a focused, well-understood platform fix with no side effects on non-Windows platforms. - The change is minimal (one file, two small hunks), addresses a clear regression with a well-documented root cause, and preserves existing behavior on Unix/macOS. The fallback guard is logically correct — no redundant fallback when already non-detached. Process cleanup paths on both platforms are unaffected. Existing tests pass because CI runs on Linux where `detached` remains `true`. - No files require special attention. _{Last reviewed commit: 5a93871} <!-- greptile_other_comments_section --> <!-- /greptile_comment -->