ci: enforce bounded build lanes

scripts/static-shards.spec.ts

@@ -0,0 +1,16 @@
+import { describe, expect, it } from 'vitest'
+import { selectStaticGates, staticShards } from './static-shards.ts'
+
+const completeInventory = staticShards.flatMap(shard => shard.gateIds).map(id => ({ id }))
+
+describe('static gate shards', () => {
+  it.each(staticShards)('selects only the gates owned by $name', (shard) => {
+    expect(selectStaticGates(completeInventory, shard.name).map(gate => gate.id)).toEqual(shard.gateIds)
+  })
+
+  it('rejects missing, duplicate, and unknown assignments', () => {
+    expect(() => selectStaticGates(completeInventory.slice(1))).toThrow('assign every static gate exactly once')
+    expect(() => selectStaticGates([...completeInventory, completeInventory[0]!])).toThrow('static gate IDs must be unique')
+    expect(() => selectStaticGates(completeInventory, 'missing')).toThrow('unknown DSH_STATIC_SHARD')
+  })
+})