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/pack.go

@@ -156,7 +156,9 @@ func packScanWhich(pack []*Object, obj *Object, i, lp int) (int, int) {
 // anything else marks the insertion point (the matched-subtype switch
 // of pack.c add_pack). It returns the resulting entry, the insert-after
 // index, whether a merge happened, and ok false when the pack is full.
-func (g *RogueGame) packMatch(obj, op *Object, i int, fromFloor bool) (*Object, int, bool, bool) {
+func (g *RogueGame) packMatch(
+	obj, op *Object, i int, fromFloor bool,
+) (*Object, int, bool, bool) {
 	switch {
 	case op.Kind.MergesInPack():
 		if !g.packRoom(fromFloor, obj) {
@@ -175,7 +177,9 @@ func (g *RogueGame) packMatch(obj, op *Object, i int, fromFloor bool) (*Object,
 
 // packMatchGroup rejoins a grouped missile bundle with its group entry
 // (the o_group arm of pack.c add_pack).
-func (g *RogueGame) packMatchGroup(obj *Object, i int, fromFloor bool) (*Object, int, bool, bool) {
+func (g *RogueGame) packMatchGroup(
+	obj *Object, i int, fromFloor bool,
+) (*Object, int, bool, bool) {
 	p := &g.Player
 
 	lp := i
@@ -333,6 +337,7 @@ func (g *RogueGame) pickUp(ch byte) {
 // everything, KindCallable takes anything nameable (not food, not the
 // amulet), KindRingOrStick takes rings and wands.
 func matchesFilter(kind ObjectKind, item *Object) bool {
+	//nolint:exhaustive // C-faithful: only the cases C handled (approved 2026-07-07)
 	switch kind {
 	case KindNone:
 		return true