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/scrolls.go

@@ -16,16 +16,19 @@ var idType = [ScrollIdentifyRingOrStick + 1]ObjectKind{
 // (scrolls.c read_scroll).
 func (g *RogueGame) readScroll() {
 	p := &g.Player
+
 	obj := g.getItem("read", KindScroll)
 	if obj == nil {
 		return
 	}
+
 	if obj.Kind != KindScroll {
 		if !g.Options.Terse {
 			g.msg("there is nothing on it to read")
 		} else {
 			g.msg("nothing to read")
 		}
+
 		return
 	}
 	// Calculate the effect it has on the poor guy.
@@ -50,30 +53,39 @@ func (g *RogueGame) readScroll() {
 		// Hold monster scroll.  Stop all monsters within two spaces from
 		// chasing after the hero.
 		held := 0
+
 		for x := p.Pos.X - 2; x <= p.Pos.X+2; x++ {
 			if x < 0 || x >= NumCols {
 				continue
 			}
+
 			for y := p.Pos.Y - 2; y <= p.Pos.Y+2; y++ {
 				if y < 0 || y > NumLines-1 {
 					continue
 				}
+
 				if mp := g.Level.MonsterAt(y, x); mp != nil && mp.On(Awake) {
 					mp.Flags.Clear(Awake)
 					mp.Flags.Set(Held)
+
 					held++
 				}
 			}
 		}
+
 		if held > 0 {
-			g.addmsg("the monster")
+			g.addmsgf("the monster")
+
 			if held > 1 {
-				g.addmsg("s around you")
+				g.addmsgf("s around you")
 			}
-			g.addmsg(" freeze")
+
+			g.addmsgf(" freeze")
+
 			if held == 1 {
-				g.addmsg("s")
+				g.addmsgf("s")
 			}
+
 			g.endmsg()
 			g.Items.Scrolls[ScrollHoldMonster].Know = true
 		} else {
@@ -83,13 +95,16 @@ func (g *RogueGame) readScroll() {
 		// Scroll which makes you fall asleep
 		g.Items.Scrolls[ScrollSleep].Know = true
 		g.NoCommand += g.rnd(g.spread(5)) + 4 // SLEEPTIME
+
 		p.Flags.Clear(Awake)
 		g.msg("you fall asleep")
 	case ScrollCreateMonster:
 		// Create a monster: first look in a circle around him, next try
 		// his room, otherwise give up
 		i := 0
+
 		var mp Coord
+
 		for y := p.Pos.Y - 1; y <= p.Pos.Y+1; y++ {
 			for x := p.Pos.X - 1; x <= p.Pos.X+1; x++ {
 				// Don't put a monster on top of the player.
@@ -103,12 +118,14 @@ func (g *RogueGame) readScroll() {
 							continue
 						}
 					}
+
 					if i++; g.rnd(i) == 0 {
 						mp = Coord{Y: y, X: x}
 					}
 				}
 			}
 		}
+
 		if i == 0 {
 			g.msg("you hear a faint cry of anguish in the distance")
 		} else {
@@ -126,10 +143,11 @@ func (g *RogueGame) readScroll() {
 		g.msg("oh, now this scroll has a map on it")
 		// take all the things we want to keep hidden out of the window
 		for y := 1; y < NumLines-1; y++ {
-			for x := 0; x < NumCols; x++ {
+			for x := range NumCols {
 				pp := g.Level.At(y, x)
 				ch := pp.Ch
 				pass := false
+
 				switch ch {
 				case Door, Stairs:
 				case '-', '|':
@@ -168,13 +186,17 @@ func (g *RogueGame) readScroll() {
 						ch = ' '
 					}
 				}
+
 				if pass {
 					if !pp.Flags.Has(FReal) {
 						pp.Ch = Passage
 					}
+
 					pp.Flags.Set(FSeen | FReal)
+
 					ch = Passage
 				}
+
 				if ch != ' ' {
 					if tp := pp.Monst; tp != nil {
 						tp.OldCh = ch
@@ -190,13 +212,17 @@ func (g *RogueGame) readScroll() {
 	case ScrollFoodDetection:
 		// Food detection
 		found := false
+
 		g.scr.Hw.Clear()
+
 		for _, fo := range g.Level.Objects {
 			if fo.Kind == KindFood {
 				found = true
+
 				g.scr.Hw.MvAddCh(fo.Pos.Y, fo.Pos.X, Food)
 			}
 		}
+
 		if found {
 			g.Items.Scrolls[ScrollFoodDetection].Know = true
 			g.showWin("Your nose tingles and you smell food.--More--")
@@ -206,7 +232,9 @@ func (g *RogueGame) readScroll() {
 	case ScrollTeleportation:
 		// Scroll of teleportation: make him disappear and reappear
 		curRoom := p.Room
+
 		g.teleport()
+
 		if curRoom != p.Room {
 			g.Items.Scrolls[ScrollTeleportation].Know = true
 		}
@@ -215,11 +243,13 @@ func (g *RogueGame) readScroll() {
 			g.msg("you feel a strange sense of loss")
 		} else {
 			p.CurWeapon.Flags.Clear(Cursed)
+
 			if g.rnd(2) == 0 {
 				p.CurWeapon.HPlus++
 			} else {
 				p.CurWeapon.DPlus++
 			}
+
 			g.msg("your %s glows %s for a moment",
 				g.Items.Weapons[p.CurWeapon.Which].Name, g.pickColor("blue"))
 		}
@@ -248,6 +278,7 @@ func (g *RogueGame) readScroll() {
 			g.msg("you feel a strange sense of loss")
 		}
 	}
+
 	g.look(true) // put the result of the scroll on the screen
 	g.status()