crane export: phased ladder + end summary

[stillalearner]

Title

feat(export): phased progress banner and summary for namespace export

Proposed Target Output (example)

What users should see (stderr / logrus; illustrative):

$ crane export -e ./out --namespace shop

crane export
namespace: shop
export-dir: ./out

[1/5] Discovery … ok (preferred API lists refreshed)
[2/5] Listing namespace resources … 38 API types with ≥1 object
      (use --debug to list each type)
[3/5] Related cluster-scoped RBAC/SCC … 4 resources → resources/shop/_cluster/
[4/5] Related CRDs … 1 fetched, 0 skipped
[5/5] Writing YAML … 412 files written

Summary
-------
resources:  ./out/resources/shop/  (+ _cluster/)
failures:   ./out/failures/shop/     (3 list/write issues recorded)
duration:   1m 04s
Done.

Description

Context

Users running crane export see no opening line, no clear sense of progress, and duplicated-looking waves of messages (“adding resource” then “Writing objects”). Failures appear as warnings without a final rollup. The target UX is: numbered phases, aggregate counts, and a Summary with paths, failure counts, and duration.

User outcome

After this issue, a typical run shows:

• First lines: crane export, namespace, export-dir.
• Phases such as: Discovery → Listing → Related cluster RBAC/SCC → Related CRDs → Writing YAML (wording can match implementation).
• Final Summary: resource root path (resources/<ns>/, _cluster/ note), failures/ path if used, count of recorded issues, duration, clear “Done.”

Scope

• Implement phased output using foundation from Issue 1 (or inline if Issue 1 is split).
• Phase lines include aggregate numbers (e.g. “38 API types with ≥1 object”) instead of listing each type at Info.
• Mid-run warnings remain visible or roll into summary; Summary must state how many list/write issues were recorded when failures/ is populated.

Acceptance criteria

• Opening banner: command name, namespace(s), export directory.
• Numbered phases with clear completion (ok / skipped counts where applicable).
• Closing Summary: key paths, failure/issue count, duration.
• With --debug, retain or improve detailed per-type logs for support.
• Manual smoke: small and large namespace.

[github-actions]

This issue is currently awaiting triage.
If contributors determine this is a relevant issue, they will accept it by applying the triage/accepted label and provide further guidance.
The triage/accepted label can be added by org members by writing /triage accepted in a comment.