fix(cli): statusline never abbreviates home-relative paths on Windows

[0xMudit]

What happened

The statusline never abbreviates home-relative paths on Windows: shortenCwd (packages/cli/src/pi-transcript.ts:1520-1525) is POSIX-only:

if (home && cwd.startsWith(home + '/')) return `~${cwd.slice(home.length)}`;

On win32, os.homedir() returns C:\Users\<name> and process.cwd() uses backslashes, so cwd.startsWith(home + '/') is false for every subdirectory of the profile directory — only the exact-home case matches. The statusline shows the full absolute path (C:\Users\<name>\Videos\...) instead of ~/Videos/..., silently no-oping the documented feature (/Users/alice/workspace/project → ~/workspace/project) on Windows rather than degrading explicitly.

How to reproduce

1. On Windows, run maka (TUI) from any directory under %USERPROFILE%
2. The statusline's last segment shows the full absolute path instead of a ~/-relative form

Suggested fix

Normalize separators before comparing (e.g. compare separator-normalized forms of cwd and home, or use path.relative(home, cwd) and reject results starting with ..), then emit ~/<rest> with native separators.