Caravans

Missing depot pruning — a depot that's gone no longer stays knotted on the khipu forever. A storage run that reaches a recorded depot and finds no container there now keeps count, and clears the dead entry for you:

• A depot found missing (broken, moved, or swapped for another block) gets a strike; two runs in a row and it's untied from your khipu and homes.yml is saved.
• A depot found standing clears its strikes; one in an unloaded chunk, or one the courier never reached because its packs were already empty, never counts.
• One yellow action-bar line when the run ends, folded into the return line: Caravan back — depot 120, 64, -30 not found., then Caravan back — missing depot 120, 64, -30 untied from khipu. Never chat.
• Item-safe: pruning only edits the depot list, and whatever didn't fit still rides home with the courier, exactly as before.
• New storage-run config keys: prune-missing-depots (default true; false is 0.0.18's exact behaviour) and prune-after-misses (default 2).
• Strikes live in memory and reset on restart, so a restart can only delay a prune, never cause one; re-recording or forgetting a depot clears its strikes.
• Verified by the unit suite (81 tests) and a clean build. The new code uses only long-standing Bukkit API (World#isChunkLoaded, org.bukkit.block.Container), so server compatibility is unchanged from 0.0.18: Paper and Purpur, 1.20 through 26.2.
• Purpur: keep mobs.llama.ridable at its default false — a WASD-ridable llama lets a rider steer against the caravan driver.