Summary

resolveScriptInterpreter in src/cron/exec-script.ts maps file extensions to interpreter binaries, but Windows-native script formats (.cmd, .bat, .ps1) are not covered. On Windows, these require explicit interpreters — cmd.exe /C for .cmd/.bat and powershell.exe -NoProfile -ExecutionPolicy Bypass -File for .ps1.

Problem

A user on Windows who creates a cron script job with a .bat, .cmd, or .ps1 command path gets a spawn error or ENOENT because the function returns null (direct execution), which requires the executable bit — a concept that doesn't exist on Windows. The script will not run.

Acceptance Criteria

• .cmd and .bat extensions map to cmd.exe with /C flag (or equivalent) on Windows
• .ps1 extension maps to powershell.exe with -NoProfile -ExecutionPolicy Bypass -File on Windows
• On non-Windows platforms, these extensions return null (not applicable; user gets a clear error if they try)
• Existing POSIX interpreter mappings (.sh, .bash, .zsh, .js, .py, etc.) are unaffected
• A test covers Windows extension detection (can use process.platform mocking or platform guard)
• pnpm build && pnpm check && pnpm test -- src/cron/exec-script.test.ts passes

Implementation Plan

1. In resolveScriptInterpreter, add a platform guard (process.platform === "win32") for Windows-specific cases:
   • .cmd, .bat → ["cmd.exe", "/C"] (interpreter + leading args)
   • .ps1 → ["powershell.exe", "-NoProfile", "-ExecutionPolicy", "Bypass", "-File"]
2. The return type needs to change from string | null to { cmd: string; leadingArgs?: string[] } | null (or similar) so the caller can prepend interpreter args before the script path.
3. Update the execCmd/execArgs construction in execCronScript to handle the new shape.
4. Add platform-conditional test cases.

Files Affected

• src/cron/exec-script.ts — resolveScriptInterpreter + call site
• src/cron/exec-script.test.ts — new test cases with platform guard

Notes

• cmd /C <path> runs a .bat/.cmd script and exits after completion — correct semantics for cron.
• PowerShell's -ExecutionPolicy Bypass is needed because the default policy blocks unsigned scripts; consistent with the OC Windows smoke harness pattern (CLAUDE.md).
• Cross-platform scripts (.js, .py, etc.) already work on Windows via the existing mappings since node and python3 are in PATH when properly installed.