v1.2.0

Tracks the MCP server's 1.2.0 release, which adds Minecraft 26.3 as a fifth target and new
tools. Nothing in the plugin broke on 1.2.0 or 26.3: the terrain scatter sends only registered
feature ids, so 26.3's flattened feature format does not reach it, and no skill used a renamed or
removed tag. This release brings the versions and counts up to date and puts the new tools where
skills can use them.

Changed

• Minecraft 26.3 is a supported target and the default for new setups (setup-fabric,
  setup-mod, minecraft-mcp-setup, README). Example jars are minecraft-fabric-mcp-1.2.0+26.3
  and fabric-api-0.165.0+26.3; setup-mod lists each target's minimum Fabric API, since a jar
  now refuses an older one. The JDK text reads Java 21 for 1.21.11 and Java 25 for every 26.x
  (it said 26.1.x, already stale for 26.2).
• setup-fabric and setup-connect: a 26.3 dedicated server defaults to white-list=true, so
  the player cannot join until whitelisted or the setting is turned off.
• Tool counts: 195 defined, up to 189 on the world server depending on Minecraft version and
  loaded modules (reference/execution/engine-limits.md, the itest harness and README).
• fluid.flow (26.2+, needs a filters.region) joins the deliverable event types in
  exec-inspect and system-redstone, with a recipe for verifying water elevators and feeds.
  The chat recipes filter on chat_type: minecraft:chat, because on 26.2+ player.chat also
  fires for /say, /msg and /me.

Added

• level_get_mob_spawns checks in survey-site, the mob-farm design notes, transit tunnels and
  biome painting: read what can spawn at a position, structure overrides included, instead of
  assuming.
• itemstack_describe include_values for verifying item components against the SNBT a build
  wrote (design-building, design-house, design-monument).
• block_transform_preview (26.3) pointers for stripped logs, paths and copper scraping, and
  content_registry_get_fuel / is_compostable sizing notes for furnace banks and composters.
• The new rainLevel / thunderLevel fields in survey-site, and a note on the new 26.3 game rule
  projectiles_can_break_blocks in engine-limits.md.
• itest cases for level_get_mob_spawns, block_transform_preview, block_family_variants and
  level_poi_query, plus checks for the new get_fuel fields, the weather levels, inline feature
  definitions, fluid.flow and the 26.3 repeat-fill_biome error. The baseline is regenerated
  against a 1.2.0 server on 26.3.
• scripts/validate-plugin.mjs fails when plugin.json and marketplace.json disagree on the
  version.

Fixed

• tools/itest/cases/level.py: the weather case skipped whenever the read lagged, which would
  have hidden a regression of the server's weather fix. Against mod 1.2.0 the first read must now
  match. The fill_biome case probed the corner of its box, where vanilla's seed-dependent biome
  jitter can read a neighbouring cell; it now paints a wider box and probes its centre.
• The itest harness explains a version-gated tool's absence (block_transform_preview below 26.3,
  content_registry_set_compostable on 26.3) instead of reporting "cause undetermined".