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/game.go

@@ -166,15 +166,18 @@ func NewGame(cfg Config) *RogueGame {
 	g.Msgs.SaveMsg = true
 	g.scr = NewScreen(cfg.Term)
 	g.FileName = cfg.Home + "/rogue.save"
+
 	g.rogueOpts = cfg.RogueOpts
 	if cfg.Wizard {
 		g.Player.Flags.Set(SenseMonsters)
 	}
+
 	if cfg.RogueOpts != "" {
 		g.ParseOpts(cfg.RogueOpts)
 	}
 
 	g.Monsters = monsterTable
+
 	g.Items.Group = 2 // weapons.c: int group = 2
 	for i := range g.Level.Passages {
 		g.Level.Passages[i].Flags = Gone | Dark
@@ -186,20 +189,26 @@ func NewGame(cfg Config) *RogueGame {
 	g.initColors()    // set up colors of potions
 	g.initStones()    // set up stone settings of rings
 	g.initMaterials() // set up materials of wands
+
 	return g
 }
 
 // Run plays the game to its end: the back half of main.c main() plus
 // playit(). It returns after death, victory, quitting, or saving.
-func (g *RogueGame) Run() (err error) {
+func (g *RogueGame) Run() error {
+	// A gameEnd panic is the port's my_exit(): recovering it here makes
+	// Run return normally (zero values), restoring the terminal via the
+	// caller's defers.
 	defer func() {
 		if r := recover(); r != nil {
 			if _, ok := r.(gameEnd); ok {
 				return // normal game over / save exit
 			}
+
 			panic(r)
 		}
 	}()
+
 	if !g.restored {
 		g.NewLevel() // draw current level
 		// Start up daemons and fuses
@@ -208,7 +217,9 @@ func (g *RogueGame) Run() (err error) {
 		g.Fuse(DSwander, 0, wanderTime(g), After)
 		g.StartDaemon(DStomach, 0, After)
 	}
+
 	g.playit()
+
 	return nil
 }
 
@@ -226,10 +237,12 @@ func (g *RogueGame) playit() {
 	}
 
 	g.Oldpos = g.Player.Pos
+
 	g.Oldrp = g.roomin(g.Player.Pos)
 	for g.Playing {
 		g.command() // command execution
 	}
+
 	g.endit()
 }
 
@@ -242,7 +255,7 @@ func (g *RogueGame) endit() {
 func (g *RogueGame) fatal(s string) {
 	g.mvaddstr(NumLines-2, 0, s)
 	g.refresh()
-	g.myExit(0)
+	g.myExit()
 }
 
 // quit has the player make certain, then exits (main.c quit). The final
@@ -252,17 +265,21 @@ func (g *RogueGame) quit(int) {
 	if !g.QComm {
 		g.Msgs.Mpos = 0
 	}
+
 	oy, ox := g.scr.Std.GetYX()
 	g.msg("really quit?")
+
 	if g.readchar() == 'y' {
 		g.clear()
-		g.scr.Std.MvPrintw(NumLines-2, 0, "You quit with %d gold pieces", g.Player.Purse)
+		g.scr.Std.MvPrintwf(NumLines-2, 0, "You quit with %d gold pieces", g.Player.Purse)
 		g.move(NumLines-1, 0)
 		g.refresh()
 		g.score(g.Player.Purse, 1, 0)
-		g.myExit(0)
+		g.myExit()
+
 		return
 	}
+
 	g.move(0, 0)
 	g.clrtoeol()
 	g.status()