feat: Implement `azdo boards iteration project list` command

[tmeckel]

Track implementation of the azdo boards iteration project list command.

Command Description

List the iteration (sprint) hierarchy for a project within an Azure DevOps organization. Iteration paths classify work by schedule and expose optional start/finish dates, all retrieved through the Work Item Tracking Classification Nodes REST API.

Command Signature

azdo boards iteration project list [organization/]<project>

• Aliases: ls, l
• Positional argument follows [organization/]<project> parsing rules with default organization fallback.

Flags

• --path, -p: Optional iteration path relative to the project root. When set, treat the node as the root for listing.
• --depth, -d: Optional integer (1–10) limiting depth. Default 3. Maps to $depth.
• --include-dates: Optional bool. When enabled, surface Start Date and Finish Date columns sourced from node attributes.
• JSON export flags wired via util.AddJSONFlags.

Behavior

1. Resolve streams, parse [organization/]<project>, and start/stop the progress indicator around API calls.
2. Acquire the Work Item Tracking client and call classificationnodes/Iterations using either GetClassificationNodes (root listing) or GetClassificationNode (scoped path) with $depth.
3. Flatten the returned tree depth-first. For each node capture: Name, fully-qualified Path, HasChildren, Level, and optionally StartDate/FinishDate. The Path must remain untouched so users can copy it directly into azdo boards work-item list --iteration.
4. When JSON export requested, emit an object with json:"nodes" containing the ordered list. Each node entry must expose a path field so scripts can feed the value to --iteration without parsing table text. Include date pointers with omitempty when requested.
5. Default path outputs a table via ctx.Printer("list") with columns Name, Path, Level, Has Children, plus date columns when --include-dates is set. Use indentation prefixes to illustrate hierarchy while keeping the Path column intact.
6. Validate --depth bounds and surface descriptive errors for invalid paths or client failures.

Testing

• Cover root listing, scoped path listing, depth truncation, JSON export (assert path presence), and error propagation using classification node mocks.

References

• List project iterations
• Classification Nodes - Get Classification Nodes (REST 7.1)