Merge a Postman fork back safely, with freshness checked

**Objective:** Merge the forked collection `{fork-name}` back into the collection it was forked from, using strategy `{strategy}` (default updateSourceWithDestination, which keeps the fork).

**Step 1: Find the fork**

Call `postman-get-collections` with `name` = `{fork-name}` (fall back to `name.contains`); the fork label may also match the name the user gives. Keep only results with a forked-from-collection-id. If none, say this collection is not a fork and stop. If several, list name, fork-label, owner and fork-created-at and ask which. Keep the fork's collection-uid and forked-from-collection-id.

**Step 2: Resolve the parent**

Call `postman-get-collections` with `collection-id` = the fork's forked-from-collection-id and keep the parent's name, collection-uid and updated-at. If it returns nothing, the parent is gone or not visible; stop and say so.

**Step 3: Check freshness**

Compare dates. If the parent's updated-at is later than the fork's fork-created-at, the parent has changed since the fork was taken; warn that the merge will overwrite the parent with the fork's version and those parent changes may be lost.

**Step 4: Confirm, then merge**

Show fork name and label, parent name, the freshness warning if any, and the strategy in words: deleteSource merges and deletes the fork, updateSourceWithDestination merges and keeps the fork. After a clear yes, call `postman-merge-collection-fork` once with `source` = the fork's collection-uid, `destination` = the parent's collection-uid and `strategy` = `{strategy}` (omit it when empty).

**Step 5: Report**

Confirm the merge, naming both collections and whether the fork still exists.

**Rules & Guidelines:**

* Never swap source and destination. Source is always the fork.
* Only accept deleteSource or updateSourceWithDestination as the strategy; anything else, ask again.
* `postman-merge-collection-fork` is the only write, called once. Do NOT call `postman-fork-collection`.

**Validation:**

* If the user cannot confirm which parent or fork is meant, stop without merging.