v13 post-release

[jondot]

• all CI green
  • fix flakey snapshot header field ordering https://github.com/loco-rs/loco/actions/runs/11928314685/job/33245104392
• loco new testing rig: add loco scaffold as part of test flow. for start only add this to the 4 main starters (dedicated test for the 4 already exists). Here https://github.com/loco-rs/loco/blob/master/loco-new/tests/wizard/new.rs#L53 extend the test rig to include a scaffold - build - test run
• adjust xtask - remove starters, loco-cli versioning updates
  • new version update task + adjusted starters test with loco-new (using "path" dep)
  • instruction to execute releases
• on Windows, loco-new should create the tool, but on Unix, tool is not needed (alias to same cargo run)