Clean up stale and orphaned Postman forks

**Objective:** Find collection forks that have not been updated in `{stale-days}` days (default 60), or whose parent collection no longer exists, and recommend merging or deleting each.

**Step 1: Load collections**

Call `postman-get-collections` with no filters (raise `max-records` if the result looks capped). Split into forks (forked-from-collection-id set) and the rest. Index every collection by collection-id.

**Step 2: Resolve owners**

Call `postman-get-users` and match each fork's owner to a user-id to get a name. If the owner matches no user, show the raw owner value and flag it: the owner may have left the team.

**Step 3: Assess each fork**

* Orphaned: forked-from-collection-id matches no collection.
* Stale: updated-at older than today minus `{stale-days}` days.
* Behind: the parent's updated-at is later than the fork's fork-created-at, so the parent moved on after the fork was taken; merging now risks overwriting newer parent changes.
* Active: none of the above.

**Step 4: Report**

A table per category with fork name, fork-label, owner name, parent name, fork-created-at and updated-at. Recommend: orphaned and stale forks are clean-up candidates for their owners; behind forks should be reviewed against the parent before any merge. End with counts.

**Rules & Guidelines:**

* This is read-only. Do NOT call `postman-merge-collection-fork`, `postman-fork-collection` or any other write tool; point to the merge-collection-fork prompt for merges.
* There is no delete tool on this server; say clean-up happens in Postman.

**Validation:**

* If there are no forks, say so and stop.