Add vanilla parity harness and harden server boundaries

Makefile

@@ -1,10 +1,19 @@
-.PHONY: test test-race verify
+.PHONY: build vet test test-race parity verify
+
+build:
+	go build ./...
+
+vet:
+	go vet ./...
 
 test:
 	go test ./...
 
 test-race:
-	go test -race ./internal/network ./internal/server ./internal/world \
-		-run 'Test(Integration|BoundaryEdit|PlayerInfo|PlayerRegistry|Concurrent|Incremental|EncodeLight|Cache|Store|Eviction|Region|Ticket|Streamer|LoadSixteen)'
+	go test -race ./...
 
-verify: test test-race
+parity:
+	test -f internal/world/testdata/vanilla_overworld_12345.bin
+	REGIONIO_REQUIRE_PARITY=1 go test ./internal/world -run TestVanillaBlockParity
+
+verify: build vet test test-race