Fix WSL shell profile support

[sunnydark]

Summary

Fixes WSL shell profile issues introduced in the shell profiles feature (#13):

• Path translation — Windows paths (e.g. C:\Users\alexh\source\repos\project) are now converted to WSL mount paths (/mnt/c/Users/alexh/source/repos/project) via --cd flag passed to wsl.exe
• Array mutation bug — shellExtraArgs was mutating the cached profile's args array in place, causing --cd flags to accumulate across session launches. Fixed by copying the array on each use.
• Claude session fallback — WSL profiles now automatically fall back to the auto-detected Windows shell for Claude sessions, since Claude CLI session data lives on the Windows filesystem and isn't accessible from inside WSL. WSL profiles continue to work for plain terminal sessions.

Changes

File	What changed
main.js	Added windowsToWslPath() and isWslShell() helpers; WSL --cd path conversion; spread-copy shellProfile.args to prevent mutation; Claude sessions fall back to Windows shell when WSL profile is active

Test plan

• Select a WSL profile in settings → open a plain Terminal → verify it opens in WSL in the correct /mnt/c/... directory
• With WSL profile selected → open a Claude session → verify it falls back to the Windows shell and works normally
• Open multiple terminal sessions in sequence → verify no --cd arg accumulation (check logs)
• Switch back to a non-WSL profile → verify everything still works

🤖 Generated with Claude Code