feat: add word wrap keyboard shortcut

[alceops]

Summary

• add Alt+Z as a global word-wrap toggle shortcut
• show the shortcut in the existing keyboard shortcut registry/help dialog
• connect FilePreview Monaco word wrap to the persisted workspace preference instead of forcing wrap on

Closes #7

Verification

• Python static guard confirmed Alt+Z registration, shortcut hook mounting, preference toggle, and FilePreview wordWrap binding
• git diff --check

Note: pnpm is not installed in this cron VM, so I could not run the repo typecheck locally.