The Siege Overhaul

Follow-up to v4.28.1 after taking a second pass over the builder handoff.

• The v4.28.1 teleport dropped the builder onto the buildarea entity's exact position, which sits above the top of the wall (in the air over the footprint). That could still leave the builder falling or wedged in terrain before it started work.
• The teleport now uses the player's own position at commission time and snaps to the top surface block there. The player is standing at the core when they click commission, so it's guaranteed safe ground inside the claim.
• If the builder is already within 24 blocks of the player, no teleport happens at all and its own pathfinder handles the short walk.
• The buildarea wiring is unchanged: currentBuildArea is set directly and the builder is forced into Working state so it engages the goal on the next tick instead of scanning for work.