go: port foundation — types, RNG, tables, daemon scheduler

Module sneak.berlin/go/rogue, package game:
- types.go: all rogue.h constants, flag types, Coord/Stats/Room/ObjInfo
- creature.go/object.go: the THING union split into Creature (Player/
  Monster) and Object; slices replace the C linked lists
- level.go: Place map with the C column-major layout and chat/flat/moat/
  winat access methods
- tables.go: extern.c + init.c data (bestiary, item tables, name pools)
- rng.go: the exact C LCG (seed*11109+13849), golden-tested against a
  compiled C reference for seed compatibility
- init.go: per-game item appearance randomization (init.c)
- daemon.go/daemons.go: scheduler with DaemonID replacing function
  pointers (ids match the C save format's mapping)
- game.go: RogueGame holds all former globals; NewGame constructor

game/rng_test.go

@@ -0,0 +1,64 @@
+package game
+
+import "testing"
+
+// The golden values below were produced by the original C generator
+// (seed = seed*11109+13849; rnd(range) = abs(RN) % range) compiled and run
+// on this machine. They lock in seed compatibility with the C game.
+func TestRndMatchesCImplementation(t *testing.T) {
+	golden := map[int32][]int{
+		1:          {0, 30, 79, 7, 87, 1, 23, 7, 57, 98},
+		12345:      {92, 92, 45, 98, 24, 39, 92, 67, 3, 7},
+		2026:       {43, 90, 6, 2, 43, 34, 20, 5, 67, 71},
+		1751808000: {61, 51, 56, 99, 68, 45, 88, 50, 46, 88},
+	}
+	for seed, want := range golden {
+		r := &Rng{Seed: seed}
+		for i, w := range want {
+			if got := r.Rnd(100); got != w {
+				t.Errorf("seed %d: rnd(100) call %d = %d, want %d", seed, i, got, w)
+			}
+		}
+	}
+}
+
+func TestRollMatchesCImplementation(t *testing.T) {
+	golden := map[int32][]int{
+		1:          {6, 8, 10},
+		12345:      {10, 10, 15},
+		2026:       {10, 10, 13},
+		1751808000: {7, 9, 9},
+	}
+	for seed, want := range golden {
+		r := &Rng{Seed: seed}
+		for i, w := range want {
+			if got := r.Roll(3, 6); got != w {
+				t.Errorf("seed %d: roll(3,6) call %d = %d, want %d", seed, i, got, w)
+			}
+		}
+	}
+}
+
+// rnd(0) must return 0 without stepping the generator: the C macro
+// short-circuits before evaluating RN, and BEFORE/AFTER depend on it.
+func TestRndZeroDoesNotStep(t *testing.T) {
+	r := &Rng{Seed: 42}
+	if got := r.Rnd(0); got != 0 {
+		t.Fatalf("rnd(0) = %d, want 0", got)
+	}
+	if r.Seed != 42 {
+		t.Fatalf("rnd(0) stepped the generator: seed = %d, want 42", r.Seed)
+	}
+}
+
+// spread(1)==1 and spread(2)==2 deterministically; the C BEFORE/AFTER
+// constants rely on this.
+func TestSpreadSmallValues(t *testing.T) {
+	g := &RogueGame{Rng: &Rng{Seed: 7}}
+	if got := g.spread(1); got != 1 {
+		t.Errorf("spread(1) = %d, want 1", got)
+	}
+	if got := g.spread(2); got != 2 {
+		t.Errorf("spread(2) = %d, want 2", got)
+	}
+}