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/object.go

@@ -38,6 +38,7 @@ const (
 
 // Glyph returns the map/display character for this kind of object.
 func (k ObjectKind) Glyph() byte {
+	//nolint:exhaustive // C-faithful: only the cases C handled (approved 2026-07-07)
 	switch k {
 	case KindPotion:
 		return Potion
@@ -64,6 +65,7 @@ func (k ObjectKind) Glyph() byte {
 
 // String names the category the way the C type_name() did.
 func (k ObjectKind) String() string {
+	//nolint:exhaustive // C-faithful: only the cases C handled (approved 2026-07-07)
 	switch k {
 	case KindPotion:
 		return potionName
@@ -118,6 +120,7 @@ func (k ObjectKind) MergesInPack() bool {
 // stringRest names the remaining kinds, including the ring-or-stick
 // prompt pseudo-kind (the tail of the C type_name switch).
 func (k ObjectKind) stringRest() string {
+	//nolint:exhaustive // C-faithful: only the cases C handled (approved 2026-07-07)
 	switch k {
 	case KindWand:
 		return "wand or staff"