Pet Door

# Pet Door

Pet Door adds a wooden pet door that lets tamed cats and wolves move through a
wall without leaving a gap open. Place it in a wall, and the flap opens
automatically when a pet is nearby.

## What it does

- Adds `petdoor:pet_door`, a wooden block with `facing`, `open`, and `locked`
  states.
- Scans every 10 ticks (twice per second) for tamed cats, wolves, and other
  `TamableAnimal`s within 1.5 blocks of the block centre.
- Opens the flap while a tamed pet is nearby, closes it when the pet leaves, and
  plays the vanilla wooden trapdoor open/close sound only when the state
  changes.
- Hostile mobs never trigger the door.
- Right-click toggles the lock. A locked door stays closed and ignores pets; an
  action-bar message confirms the change.
- The closed door has a full-face outline and collision. When open, the outline
  is the frame only and collision is empty, leaving the 12×12 opening passable.
- Drops itself when broken by hand or axe; an axe is faster.

## Why use it

A normal door or an open hole lets everything through. Pet Door gives tamed pets
their own way in and out while keeping the wall visually closed. It is a single
block with no GUI, config, or new entities, so it fits into existing builds and
modpacks without setup.

## What it does not do

- Does not change pet AI or pathfinding. Pets still need to path to the door on
  their own.
- Does not guarantee that a hostile mob cannot follow a pet through the briefly
  open flap. V1 has no per-entity collision filtering.
- Does not add a new entity, redstone support, GUI, config, networking, or world
  generation.
- Only reacts to mobs that extend `TamableAnimal`; custom tamed mobs from other
  mods may not trigger it.
- Is a 2px-thick wall block, not a full-size hinged door.

## Crafting

- 3x any planks
- 1x leather

Output: 1 Pet Door

## Placement

Place the Pet Door in a wall. It faces you when placed, matching a furnace.
Right-click to lock or unlock it.