Pier 26.51.1

Built for BDS 1.26.51 and LeviLamina 26.51.5. A release is built against the one BDS its
number names, so 26.40.3 stays the build for BDS 1.26.40 and does not run on 1.26.51.
None of the engine changes reaches the ABI: PIER_ABI_VERSION stays at 2 and a mod built
against 26.40.3 keeps working without a rebuild. One behaviour does change for mods: an
ability or permission level written before the player has finished joining is now
refused, see below.

Added

• Literal subcommands in register_command_ex. A parameter of kind text, with the
  word in its text field, declares a literal: a node in the command tree, which is what
  /scoreboard objectives add is made of, and the only form the client narrows as the
  player types. An enum parameter lists its values but is not a tree node, so the
  client had nothing to filter on, and the spec had no way to ask for a literal. The
  handler receives the word under the parameter's name like any other argument, so
  dispatch does not depend on an overload index that moves when an overload is inserted
  above it. Two overloads that differ only by a literal digest differently, so a reload
  cannot rebind one onto the other. In pier-rs this is OverloadBuilder::text(name, literal). A host before 26.51.1 rejects the kind as unknown and does not register the
  command.

Changed

• Ability and permission-level writes wait until the player has finished joining.
  PIER_PACT_SET_ABILITY and PIER_PACT_SET_PERMISSION_LEVEL return false, with a
  warning in the log, until Player::isPlayerInitialized. Written earlier, the change
  reaches a client that has not built its ability layers yet: server and client then
  disagree, and the player can be left unable to build or attack until they rejoin. The
  write is refused rather than queued, so a caller that tried too early finds out at the
  call instead of seeing the change land at an unrelated moment. Simulated players have
  no client and are exempt. A mod that sets abilities while a player joins has to make
  the write once the player has fully joined.
• PIER_SRV_PROTOCOL_VERSION knows 1.26.51, which speaks 2193, read from the
  startup banner of a 1.26.51 server like the 1.26.40 row before it.
• Custom dimension registration passes the whole definition.
  DimensionManager::_registerCustomDimensionWithDimensionDefinitionGroup is gone in
  26.51. Its replacement, _registerDimensionWithDimensionDefinitionGroup, takes a
  complete DimensionDefinition, so the height and the generator go in at registration
  instead of being corrected afterwards. The definition carries the 1.26.50
  minecraft:dimension_height shape, mMinY and mHeightRange, in place of a minimum
  and a maximum. The top of a dimension is mMinY + mHeightRange, and the
  dimension-data trace prints it that way.
• MobEffectInstance has its two-argument constructor back. 26.51 exports
  MobEffectInstance(id, duration) again and declares the default constructor without
  defining it. Adding an effect builds the instance through that constructor and assigns
  the amplifier and the visibility; every other field is what the engine's constructor
  sets rather than value-initialized.
• Common::getGameVersionString is gone on the server. PIER_SRV_BDS_VERSION reads
  Common::StringConstants::mGameVersionString instead, built once through
  Common::_buildStringConstants.
• GameMode::useItemOn takes a HandSlot, and the PlayerUseItemOnEvent hook
  passes it through unchanged. The event payload is unchanged.
• VoidGenerator takes the default biome as a constructor argument. A void
  dimension passes the biome its spec names, or plains when that one is missing, as
  before.
• ChunkState lost NeighborAwareUpgradeNeeded and NeighborAwareUpgrading, and
  the chunk trace no longer names them.
• The Rust binding moves to pier-rs 2.1.0 / pier-sys-rs 26.51.1.