Added

• CoreProtect integration to detect historical player-placed blocks, with cache and configurable lookback.
• /lavacast coreprotect and /lavacast coreprotectlookback commands.
• Disk-backed mark storage per chunk when CoreProtect is unavailable.
• /lavacast mark radius command to manually mark nearby blocks as player-based for height checks (max 100)

Changed

• Lava flow blocking now applies only to player-placed lava; natural lava flows normally.
• Replaced in‑memory placed‑block tracking with disk‑backed per‑chunk mark files (used by /lavacast mark) when CoreProtect isn’t available.