chore(lint): adopt canonical golangci-lint config

Replace .golangci.yml with the shared canonical config. The old
config's top-level linters-settings block was silently ignored under
the v2 schema, so the lll/funlen/cyclop/dupl thresholds now actually
apply. The four repo-specific disables (mnd, exhaustive, paralleltest,
testpackage) move out of the config into targeted in-code nolint
directives carrying their original approval dates, keeping the config
byte-identical to the canonical one.

Fixes surfaced by the stricter settings: t.Parallel() added to all 32
tests, 24 overlong lines wrapped or their comments tightened, tcell
control-code returns rewritten as character literals, dupl markers on
the identically-shaped item data tables, and two wsl_v5 defer cuddles.

No behavior changes. The repo has no golangci-lint version pin (no
Dockerfile or CI; make lint runs the host binary, currently v2.12.2),
so there was nothing to bump.

game/tables_test.go

@@ -1,9 +1,12 @@
+//nolint:testpackage // white-box tests reach unexported state (approved 2026-07-07)
 package game
 
 import "testing"
 
 // badcheck from init.c: every probability table must sum to exactly 100.
 func TestProbabilitiesSumTo100(t *testing.T) {
+	t.Parallel()
+
 	sum := func(info []ObjInfo) int {
 		s := 0
 		for _, oi := range info {
@@ -32,6 +35,8 @@ func TestProbabilitiesSumTo100(t *testing.T) {
 }
 
 func TestInitProbsCumulative(t *testing.T) {
+	t.Parallel()
+
 	g := New(Params{Seed: 1})
 
 	last := g.Items.Potions[NumPotionTypes-1].Prob
@@ -47,6 +52,8 @@ func TestInitProbsCumulative(t *testing.T) {
 }
 
 func TestNewGameRandomizesAppearances(t *testing.T) {
+	t.Parallel()
+
 	g := New(Params{Seed: 12345})
 
 	checkPotionColors(t, g)
@@ -112,6 +119,8 @@ func checkWandMaterials(t *testing.T, g *RogueGame) {
 }
 
 func TestMonsterTable(t *testing.T) {
+	t.Parallel()
+
 	data := newGameData()
 	if data.monsterTable[0].Name != "aquator" || data.monsterTable[25].Name != "zombie" {
 		t.Error("monster table order broken")