feat(windows): the ludic CLI and ludic bundle on Windows

The CLI's shell commands go through shell(), which is run() on POSIX and a
scratch script handed to Git for Windows' bash on Windows (exit codes read
directly there). compile_app links through `ludicc -o` on Windows, ludic run
starts the .exe, and ludic-dev build and ensure_ludicc assemble
selfhost/ludicc.win.seed.ll, which ludic-dev reseed now writes beside the
macOS seed. ludic bundle makes build/<name>/ with a GUI-subsystem exe carrying
the .ico beside `app icon` as an llvm-rc resource, game.lpak and packs.index;
ludicc gains --gui and --link, and quotes its whole link line for cmd.exe.

Verified: ludic-dev test 135/135, selfhost-test 32/32; on the PC a checkout
bootstraps from the Windows seed, ludic-dev build makes the toolchain, and
`ludic bundle` makes build/Maroon Lake/, which runs from its own folder.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tools/ludic-cli/forgejo.ludic

@@ -20,7 +20,7 @@ var forgejo_hdr: pointer = null
 function forgejo_headers() -> pointer {
   if forgejo_hdr == null {
     forgejo_hdr = tmp_path("forgejo_headers.txt")
-    run(`umask 077 && printf 'Authorization: token %s\n' "$FORGEJO_TOKEN" > {forgejo_hdr}`)
+    shell(`umask 077 && printf 'Authorization: token %s\n' "$FORGEJO_TOKEN" > {forgejo_hdr}`)
   }
   return forgejo_hdr
 }