AutoCraft MineShaft v2.1 — Protected Home + Floor Mementos

GAME MODES
- Home Room is Survival mode.
- Floors 1–10 are Adventure mode.
- First join, resume, death return and ordinary Home return all resolve to Survival.
- Safety Rope teleports Home and then explicitly applies Survival mode.
- A tick failsafe repairs an incorrect mode based on arpg2_room.

HOME PROTECTION
- Added DAI 1.9.9 player_start_break_block cancel reactions for the authored Home shell.
- Main Home floor, ceiling and four outer walls are protected.
- Farm floor, ceiling and outer walls are protected.
- North lift iron-bar framing is protected.
- Protection is coordinate-plane based, so it does not blanket-lock interior crops, barrels, crafting stations or other usable blocks.

FLOOR MEMENTOS
- Removed the old next-floor sigil crystal rewards.
- Every boss clear now awards a memento representing the floor just cleared.
- Floors 1–10 each have their own item, name and lore.
- Existing saves receive historical mementos based on arpg2_unlock; Floor 10 requires arpg2_campaign_clear.
- Progression remains scoreboard-owned, so losing/storing a trophy cannot relock a floor.

DAI target: 1.9.9.
