Adventure Tents Dynamic Sleep Height Validation

Behavior verified in pack source:
- Unoccupied body shell: 0.320 blocks tall.
- Unoccupied pillow shell: 0.380 blocks tall.
- Occupied body shell: 0.480 blocks tall.
- Occupied pillow shell: 0.530 blocks tall.
- State source: the real minecraft:straw_bed occupied=true block state.
- Applies to standalone Sleeping Bags and sleeping surfaces in Small, Medium, and Large tents.
- Per-tick state checks are limited to native sleep cosmetic displays near players.
- A low-frequency heartbeat lowers stale raised visuals after unusual disconnect/leave cases.
- Native Straw Bed placement, sleep behavior, packing, tent IDs, structures, and reliability logic were not redesigned.

Static validation:
- 111 JSON files parsed successfully.
- 548 functions indexed.
- 378 functions reachable from load/tick/advancement roots.
- 0 missing function targets in the reachable/live graph.
- All new dynamic raise/lower/update functions are reachable.
- ZIP integrity test passed.

Legacy note:
Four old _extract_shulker_* helper files still refer to the pre-existing missing _extract_barrel_generic helper, but those files remain unreachable from the live execution graph exactly as before and were not modified for this visual change.
