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/daemons.go

@@ -45,6 +45,7 @@ func (g *RogueGame) doctor(int) {
 	p := &g.Player
 	lv := p.Stats.Lvl
 	ohp := p.Stats.HP
+
 	g.Quiet++
 	if lv < 8 {
 		if g.Quiet+(lv<<1) > 20 {
@@ -53,16 +54,20 @@ func (g *RogueGame) doctor(int) {
 	} else if g.Quiet >= 3 {
 		p.Stats.HP += g.rnd(lv-7) + 1
 	}
+
 	if p.IsRing(Left, RingRegeneration) {
 		p.Stats.HP++
 	}
+
 	if p.IsRing(Right, RingRegeneration) {
 		p.Stats.HP++
 	}
+
 	if ohp != p.Stats.HP {
 		if p.Stats.HP > p.Stats.MaxHP {
 			p.Stats.HP = p.Stats.MaxHP
 		}
+
 		g.Quiet = 0
 	}
 }
@@ -82,6 +87,7 @@ func (g *RogueGame) rollwand(int) {
 			g.KillDaemon(DRollwand)
 			g.Fuse(DSwander, 0, wanderTime(g), Before)
 		}
+
 		g.Daemons.Between = 0
 	}
 }
@@ -103,6 +109,7 @@ func (g *RogueGame) unsee(int) {
 			g.mvaddch(th.Pos.Y, th.Pos.X, th.OldCh)
 		}
 	}
+
 	g.Player.Flags.Clear(CanSeeInvisible)
 }
 
@@ -112,9 +119,11 @@ func (g *RogueGame) sight(int) {
 	if p.On(Blind) {
 		g.Extinguish(DSight)
 		p.Flags.Clear(Blind)
+
 		if !p.Room.Flags.Has(Gone) {
 			g.enterRoom(p.Pos)
 		}
+
 		g.msg("%s", g.chooseStr("far out!  Everything is all cosmic again",
 			"the veil of darkness lifts"))
 	}
@@ -129,6 +138,7 @@ func (g *RogueGame) nohaste(int) {
 // stomach digests the hero's food (daemons.c stomach).
 func (g *RogueGame) stomach(int) {
 	p := &g.Player
+
 	origHungry := p.HungryState
 	if p.FoodLeft <= 0 {
 		if p.FoodLeft--; p.FoodLeft < -StarveTime {
@@ -138,29 +148,36 @@ func (g *RogueGame) stomach(int) {
 		if g.NoCommand != 0 || g.rnd(5) != 0 {
 			return
 		}
+
 		g.NoCommand += g.rnd(8) + 4
 		p.HungryState = 3
+
 		if !g.Options.Terse {
-			g.addmsg("%s", g.chooseStr(
+			g.addmsgf("%s", g.chooseStr(
 				"the munchies overpower your motor capabilities.  ",
 				"you feel too weak from lack of food.  "))
 		}
+
 		g.msg("%s", g.chooseStr("You freak out", "You faint"))
 	} else {
 		oldfood := p.FoodLeft
+
 		amulet := 0
 		if g.HasAmulet {
 			amulet = 1
 		}
+
 		p.FoodLeft -= g.ringEat(Left) + g.ringEat(Right) + 1 - amulet
 
 		if p.FoodLeft < MoreTime && oldfood >= MoreTime {
 			p.HungryState = 2
+
 			g.msg("%s", g.chooseStr(
-				"the munchies are interfering with your motor capabilites",
+				"the munchies are interfering with your motor capabilities",
 				"you are starting to feel weak"))
 		} else if p.FoodLeft < 2*MoreTime && oldfood >= 2*MoreTime {
 			p.HungryState = 1
+
 			if g.Options.Terse {
 				g.msg("%s", g.chooseStr("getting the munchies", "getting hungry"))
 			} else {
@@ -169,8 +186,10 @@ func (g *RogueGame) stomach(int) {
 			}
 		}
 	}
+
 	if p.HungryState != origHungry {
 		p.Flags.Clear(Awake)
+
 		g.Running = false
 		g.ToDeath = false
 		g.Count = 0
@@ -200,8 +219,10 @@ func (g *RogueGame) comeDown(int) {
 
 	// undo the monsters
 	seemonst := p.On(SenseMonsters)
+
 	for _, tp := range g.Level.Monsters {
 		g.move(tp.Pos.Y, tp.Pos.X)
+
 		if g.cansee(tp.Pos.Y, tp.Pos.X) {
 			if !tp.On(Invisible) || p.On(CanSeeInvisible) {
 				g.addch(tp.Disguise)
@@ -214,6 +235,7 @@ func (g *RogueGame) comeDown(int) {
 			g.standend()
 		}
 	}
+
 	g.msg("Everything looks SO boring now.")
 }
 
@@ -238,17 +260,19 @@ func (g *RogueGame) visuals(int) {
 
 	// change the monsters
 	seemonst := p.On(SenseMonsters)
+
 	for _, tp := range g.Level.Monsters {
 		g.move(tp.Pos.Y, tp.Pos.X)
+
 		if g.seeMonst(tp) {
 			if tp.Type == 'X' && tp.Disguise != 'X' {
 				g.addch(g.rndThing())
 			} else {
-				g.addch(byte(g.rnd(26) + 'A'))
+				g.addch(g.randomMonsterLetter())
 			}
 		} else if seemonst {
 			g.standout()
-			g.addch(byte(g.rnd(26) + 'A'))
+			g.addch(g.randomMonsterLetter())
 			g.standend()
 		}
 	}