[cmaycumber]

A new renderoni/nav entry point: grid pathfinding for large worlds, extracted from a shipping game.

• NavGrid: generic over a NavCostField the game supplies (size, cellCost(x, z), optional coarseWalkable/passable for far-away queries that must not build tiles).
  • Tiles are sampled lazily and LRU-evicted, with pooled arrays.
  • Blockers (buildings) are re-applied when a tile rebuilds.
  • A* runs in a bounded window with generation-stamped scratch and a typed-array heap, so there's no per-search allocation.
  • It also offers nearestWalkable, lineClear, segmentWalkable and prewarm.
  • Cell size, tile size, tile cap, window, node budget, easy cost and blocker slack are all options.
• ExpeditionRouter: joins complete local paths into long corridors across the map against a small RouterNav interface, with a ticketed request API.
• SpatialHash<T>: a neighbour-query grid over anything with position: { x, z }.

The game now supplies only its cost rules (water, cliffs, slope, roads) and uses these classes directly. Its 496-test suite passes on them, including long-range navigation tests.

Verification: typecheck, build, 246/246 tests.

🤖 Generated with Claude Code

[elemarin]

Thanks, this is well built. The lazy tiles, re-applying blockers on rebuild, and the stamped typed-array A* all check out. Build, typecheck and tests (246/246) pass, and I found no correctness bugs in the A* itself.

Before merge:

1. Router input validation: an out-of-bounds or unwalkable goal burns about 1,800 local searches before failing. Please check inBounds/walkable in request() and return blocked immediately.
2. minSpacing: halving can undershoot the floor (100 → 50 → 25). Please clamp with Math.max(minSpacing, spacing / 2).
3. Costs below 1: the octile heuristic is only admissible for costs ≥ 1, so "fast" cells such as roads give non-optimal paths. Please add a minCost scale or document it.
4. Generalize: please rename ExpeditionRouter to something like RoutePlanner and drop the house/door/road wording. Use an enum reason instead of English UI strings, and plain {x, z} instead of three's Vector2. Router defaults would be better scaled from nav.cell than absolute metres.
5. Hardening: please add invalidate(x, z, r) for runtime cost changes, guard SpatialHash against non-finite radius and out-of-range coordinates, and validate n <= 46340 (Int32 index math).
6. Docs: please soften the "allocation-free" wording in AGENTS.md. The router allocates string keys and arrays per update.
7. Tests: please add cases for router failure paths, costs below 1, and SpatialHash with negative and far coordinates.

Note: this will need a small AGENTS.md rebase after #39 and #40 land.