0.82.0

This release adds `arbigent sort`, which puts the scenarios in a project YAML into dependency order and writes a `# tree:` comment above each one.

## `arbigent sort` and `# tree:` Position Comments (#441, #442)

A project with many scenarios is hard to read once children drift away from their parents. `arbigent sort` rewrites the project file so each scenario comes right after the scenario it depends on, subtree by subtree (depth-first), while roots and siblings keep their declared order. It also writes a `# tree:` comment above each scenario showing its ancestors and children, and one header line under `scenarios:` saying the comments are generated:

```yaml
scenarios:
# The "# tree:" lines below are generated from `dependency` by `arbigent sort` (and on UI save); do not edit them, rerun `arbigent sort`.
# tree: launch-app | children: open-search
- id: "launch-app"
  goal: "Launch the app"
# tree: launch-app > open-search | children: type-keyword
- id: "open-search"
  goal: "Open search"
  dependency: "launch-app"
# tree: launch-app > open-search > type-keyword
- id: "type-keyword"
  goal: "Type a keyword"
  dependency: "open-search"
```

Only the scenario blocks move and only the `# tree:` lines change; everything else in the file, including your own comments, stays byte for byte. Saving from the UI writes the same order and comments, but note that a UI save regenerates the whole file (as before), so notes that must survive belong in `noteForHumans`.

```bash
arbigent sort                     # rewrite the project file in place
arbigent sort --diff              # print what would change, exit 1 if anything would (for CI)
arbigent sort --no-comments       # sort without writing the comments
```

Set `settings.positionComments: false` in the project YAML to stop writing the comments from both the CLI and the UI.

## What's Changed
* Add arbigent sort with position comments for scenario order by @takahirom in https://github.com/takahirom/arbigent/pull/441
* Say in the sort help that it rewrites the project YAML by @takahirom in https://github.com/takahirom/arbigent/pull/442


**Full Changelog**: https://github.com/takahirom/arbigent/compare/0.81.1...0.82.0