Adopt house golangci-lint config; fix all approved-linter findings

.golangci.yml is the prompts-repo standard verbatim plus one approved
exception (paralleltest, sneak 2026-07-06). Roughly 1,500 findings
fixed:

- autofix sweep (wsl_v5/nlreturn/intrange/modernize formatting), with
  the misspell autofix REVERTED where it rewrote authentic C game text
  ("missle vanishes" stays, with nolint and a comment)
- error handling: errcheck sites get real handling — saveFile now
  closes explicitly and removes corrupt saves, scoreboard writes are
  documented best-effort, err113 sentinel errors (ErrSaveOutOfDate,
  ErrScreenTooSmall); panics allowed for unrecoverable states per
  MEMORY.md policy
- gosec: real fixes (ParseInt for SEED, 0600 scorefile) and justified
  per-line nolints for provably-bounded conversions (randomMonsterLetter
  helper collapses eight rnd(26)+'A' sites)
- API tidying from linters: pointer receivers on flag types
  (recvcheck), msg helpers renamed addmsgf/doaddf/Printwf/MvPrintwf
  (goprintffuncname), myExit()/findFloor(monst)/mkGameInput(t) drop
  always-constant params (unparam), gameEnd carries no status
- gocritic/staticcheck: if-else chains to switches, the pack.c
  inventory filter untangled into matchesFilter, main.go split so
  defers run before exit (exitAfterDefer, funlen)
- revive doc comments on all exported flag types/consts/methods

Remaining findings are confined to linters pending sneak's exception
decision (mnd, gochecknoglobals, cyclop, nestif, gocognit, exhaustive,
goconst, testpackage); TODO.md records the state. MEMORY.md added at
repo root as the project's agent working notes.

game/init.go

@@ -51,7 +51,8 @@ func (g *RogueGame) initPlayer() {
 // (init.c init_colors).
 func (g *RogueGame) initColors() {
 	used := make([]bool, len(rainbow))
-	for i := PotionKind(0); i < NumPotionTypes; i++ {
+
+	for i := range NumPotionTypes {
 		var j int
 		for {
 			j = g.rnd(len(rainbow))
@@ -59,6 +60,7 @@ func (g *RogueGame) initColors() {
 				break
 			}
 		}
+
 		used[j] = true
 		g.Items.PotColors[i] = rainbow[j]
 	}
@@ -66,8 +68,9 @@ func (g *RogueGame) initColors() {
 
 // initNames generates the names of the various scrolls (init.c init_names).
 func (g *RogueGame) initNames() {
-	for i := ScrollKind(0); i < NumScrollTypes; i++ {
+	for i := range NumScrollTypes {
 		var cp strings.Builder
+
 		nwords := g.rnd(3) + 2
 		for ; nwords > 0; nwords-- {
 			nsyl := g.rnd(3) + 1
@@ -76,10 +79,13 @@ func (g *RogueGame) initNames() {
 				if cp.Len()+len(sp) > MaxNameLen {
 					break
 				}
+
 				cp.WriteString(sp)
 			}
+
 			cp.WriteByte(' ')
 		}
+
 		g.Items.ScrNames[i] = strings.TrimSuffix(cp.String(), " ")
 	}
 }
@@ -88,7 +94,8 @@ func (g *RogueGame) initNames() {
 // (init.c init_stones).
 func (g *RogueGame) initStones() {
 	used := make([]bool, len(stoneTable))
-	for i := RingKind(0); i < NumRingTypes; i++ {
+
+	for i := range NumRingTypes {
 		var j int
 		for {
 			j = g.rnd(len(stoneTable))
@@ -96,6 +103,7 @@ func (g *RogueGame) initStones() {
 				break
 			}
 		}
+
 		used[j] = true
 		g.Items.RingStones[i] = stoneTable[j].Name
 		g.Items.Rings[i].Worth += stoneTable[j].Value
@@ -107,8 +115,10 @@ func (g *RogueGame) initStones() {
 func (g *RogueGame) initMaterials() {
 	used := make([]bool, len(woods))
 	metused := make([]bool, len(metals))
-	for i := WandKind(0); i < NumWandTypes; i++ {
+
+	for i := range NumWandTypes {
 		var str string
+
 		for {
 			if g.rnd(2) == 0 {
 				j := g.rnd(len(metals))
@@ -116,6 +126,7 @@ func (g *RogueGame) initMaterials() {
 					g.Items.WandType[i] = "wand"
 					str = metals[j]
 					metused[j] = true
+
 					break
 				}
 			} else {
@@ -124,10 +135,12 @@ func (g *RogueGame) initMaterials() {
 					g.Items.WandType[i] = "staff"
 					str = woods[j]
 					used[j] = true
+
 					break
 				}
 			}
 		}
+
 		g.Items.WandMade[i] = str
 	}
 }
@@ -166,5 +179,6 @@ func (g *RogueGame) pickColor(col string) string {
 	if g.Player.On(Hallucinating) {
 		return rainbow[g.rnd(len(rainbow))]
 	}
+
 	return col
 }