Farming & food chain (crops, farmland, food production)

[MichaelFisher1997]

Largely standalone from #1-#4 (only needs the hoe tool from #4 to till soil, and bread recipe in #1). Closes the survival food loop — currently food is eaten but never produced.

Context

Eating is fully wired today (PlayerState.ts:81 eat(), right-click eat handler in Game.ts:723-726, hunger/saturation tick in PlayerState.ts:135-141, five food items in Items.ts:39-45). But there are no wheat seeds, no hoe, no farmland block, no crop-growth tick, no animals. cooked_beef is only obtainable from the creative palette — the food chain has no production side.

Scope

• src/game/gen/BlockIds.ts — append WHEAT_CROP (multi-stage block), FARMLAND. Coordinated edit with Blocks.ts + Textures.ts per AGENTS.md.
• src/engine/Textures.ts — crop growth-stage textures (3-4 stages), farmland (dry + hydrated variants).
• src/game/Items.ts — add wheat_seeds, wheat items; add to DROP_TABLE (tall grass drops seeds).
• Hoe tool (from Water overhaul: liquid simulation, flow physics, rendering, interaction #4) — right-click grass/dirt → farmland block; consumes durability.
• Crop growth tick — new farming system (or extend the liquid/ambient tick loop) advancing wheat stages gated on:
  • light level (reuse the sun/block-light channel)
  • farmland hydration (adjacent water block within N blocks)
  • random tick probability per in-game day
• Right-click harvest on mature wheat → drops wheat + seeds (replantable).
• src/game/Recipes.ts (from Voxel lighting + day/night cycle (sun, moon, two-channel shading) #1) — 3 wheat → 1 bread.

Out of scope

Livestock breeding and passive animals are Phase 3 (mobs & creatures). This issue covers crop farming only; animal-derived food stays creative-palette-only until mobs land.

Acceptance criteria

• Till grass/dirt with a hoe to create farmland.
• Plant wheat seeds on farmland; crops advance through growth stages over in-game days when hydrated and lit.
• Mature wheat is harvestable into wheat + seeds.
• Craft bread from wheat.
• Breaking tall grass has a chance to drop seeds.

Roadmap reference

Phase 2 — "Farming & food chain".