Adventure Tents v2.3.0 — Minecraft Java 26.3 Compatibility Update

Target:
- Minecraft Java Edition 26.3
- Data Pack version 121.0

Required compatibility changes applied:
- Updated pack.mcmeta from data pack 107.1 to 121.0.
- Updated 3 standalone predicates from the old `condition` type discriminator to `type`.
- Updated the Small Tent loot entry from `functions` to `modifier`.
- Updated loot/item modifier type discriminators from `function` to `type`.
- Updated 4 inline `minecraft:copy_custom_data` item modifiers used by tent packing/recovery.
- Updated 2 `minecraft:player_interacted_with_entity` advancement entity checks to explicit `minecraft:entity_properties` predicates.

Intentionally unchanged:
- Existing /item slot strings and `execute if items` slot ranges remain valid in 26.3 and were not rewritten.
- Scoreboard, storage, packing, placement, upgrade, recipe, and sleeping-bag architecture were not redesigned.
- Historical 26.2 notes/changelogs were retained.
- Structure NBT files were not manually rewritten; their stored DataVersion allows Minecraft's data-fixer path to handle older serialized data. They must still be placement-tested in Java 26.3, especially tent structures containing furnaces or blast furnaces.

Validation gate before release use:
- Confirm clean pack load and /reload in Java 26.3.
- Place/pack Small, Medium, and Large tents.
- Verify stored-barrel recovery and upgrades.
- Verify sleeping-bag placement/use and pillow interaction.
- Verify night/thunder predicates.
- Verify furnace/blast-furnace-containing structures load with no warnings or lost state.
