AdventureTents 2.1.3 - Storage-safe packing patch

Issue addressed:
- Rare pack-time storage loss was possible because tent barrel data was written back to the saved tent ID before the pack flow had fully proven the barrel contents were actually read and saved.

What changed:
- Small, medium, and large tent extractors now only copy barrel contents into temporary storage first.
- Packing now blocks before teardown if an expected storage barrel is missing (medium/large) or if a barrel with items cannot be read.
- Packing now commits temp storage to the tent ID only after the read checks pass.
- Packing now verifies the saved tent ID contains the expected items before the tent is removed.
- Failed pack attempts now clean up stale pack markers/probes instead of leaving a tent in a half-packing state.

Expected in-game behavior:
- If the safety check fails, the tent remains placed and an actionbar warning appears.
- The tent should not be removed when the pack cannot prove the barrel contents are safely in storage.
