Rename constants to descriptive names (refactor step 1)

Pure rename, no behavior change; the full suite (RNG goldens,
generation invariants, scripted sessions, save round trip) is
unchanged and green.

- Creature flags: IsHuh→Confused, IsHalu→Hallucinating,
  CanHuh→CanConfuse, CanSee→CanSeeInvisible, IsRun→Awake,
  SeeMonst→SenseMonsters, IsCanc→Cancelled, IsLevit→Levitating,
  IsBlind/IsGreed/IsHaste/IsTarget/IsHeld/IsInvis/IsMean/IsRegen/
  IsFly/IsSlow → Blind/Greedy/Hasted/Targeted/Held/Invisible/Mean/
  Regenerates/Flying/Slowed, IsFound→Found
- Object flags: IsCursed→Cursed, IsKnow→Known, IsMissl→Missile,
  IsMany→Stackable, ObjIsFound→WasFound, IsProt→Protected
- Room flags: IsDark/IsGone/IsMaze → Dark/Gone/Maze; place flags:
  FPass→FPassage, FPNum→FPassNum, FTMask→FTrapMask
- Trap types: TDoor→TrapDoor ... TMyst→TrapMystery
- Item subtypes: P*→Potion* (PLSD→PotionLSD, PMFind→
  PotionDetectMonsters, ...), S*→Scroll* (SIDRorS→
  ScrollIdentifyRingOrStick, ...), R*→Ring* (RAddHit→RingDexterity,
  RNop→RingAdornment, ...), Ws*→Wand* (WsElect→WandLightning, ...),
  weapons (TwoSword→WeaponTwoHandedSword, Shiraken→WeaponShuriken,
  ...), armor (RingMail→ArmorRingMail, ...)
- Counts: Max{Potions,Scrolls,Rings,Sticks,Weapons,Armors} →
  Num{Potion,Scroll,Ring,Wand,Weapon,Armor}Types; NTraps→NumTrapTypes
- Level.NTraps field → TrapCount (also in the save snapshot)
- Original C constant names preserved as comment breadcrumbs in
  types.go so the lineage stays greppable

TODO.md: step 1 moved to Completed, step 2 (typed kinds) promoted to
Next Step.

game/move.go

@@ -21,7 +21,7 @@ func (g *RogueGame) doMove(dy, dx int) {
 	}
 	// Do a confused move (maybe)
 	var nh Coord
-	if p.On(IsHuh) && g.rnd(5) != 0 {
+	if p.On(Confused) && g.rnd(5) != 0 {
 		nh = g.rndmove(&p.Creature)
 		if nh == p.Pos {
 			g.After = false
@@ -52,12 +52,12 @@ over:
 		fl = *g.Level.FlagsAt(nh.Y, nh.X)
 		ch = g.Level.VisibleChar(nh.Y, nh.X)
 		if !fl.Has(FReal) && ch == Floor {
-			if !p.On(IsLevit) {
+			if !p.On(Levitating) {
 				ch = Trap
 				g.Level.SetChar(nh.Y, nh.X, Trap)
 				g.Level.FlagsAt(nh.Y, nh.X).Set(FReal)
 			}
-		} else if p.On(IsHeld) && ch != 'F' {
+		} else if p.On(Held) && ch != 'F' {
 			g.msg("you are being held")
 			return
 		}
@@ -67,8 +67,8 @@ over:
 	}
 	switch ch {
 	case ' ', '|', '-':
-		if g.Options.PassGo && g.Running && p.Room.Flags.Has(IsGone) &&
-			!p.On(IsBlind) {
+		if g.Options.PassGo && g.Running && p.Room.Flags.Has(Gone) &&
+			!p.On(Blind) {
 			var b1, b2 bool
 			switch g.RunCh {
 			case 'h', 'l':
@@ -109,13 +109,13 @@ over:
 		g.After = false
 	case Door:
 		g.Running = false
-		if g.Level.FlagsAt(p.Pos.Y, p.Pos.X).Has(FPass) {
+		if g.Level.FlagsAt(p.Pos.Y, p.Pos.X).Has(FPassage) {
 			g.enterRoom(nh)
 		}
 		g.moveStuff(nh, fl)
 	case Trap:
 		tr := g.beTrapped(nh)
-		if tr == TDoor || tr == TTelep {
+		if tr == TrapDoor || tr == TrapTeleport {
 			return
 		}
 		g.moveStuff(nh, fl)
@@ -151,7 +151,7 @@ over:
 func (g *RogueGame) moveStuff(nh Coord, fl PlaceFlags) {
 	p := &g.Player
 	g.mvaddch(p.Pos.Y, p.Pos.X, g.floorAt())
-	if fl.Has(FPass) && g.Level.Char(g.Oldpos.Y, g.Oldpos.X) == Door {
+	if fl.Has(FPassage) && g.Level.Char(g.Oldpos.Y, g.Oldpos.X) == Door {
 		g.leaveRoom(nh)
 	}
 	p.Pos = nh
@@ -161,7 +161,7 @@ func (g *RogueGame) moveStuff(nh Coord, fl PlaceFlags) {
 // (move.c turn_ok).
 func (g *RogueGame) turnOk(y, x int) bool {
 	pp := g.Level.At(y, x)
-	return pp.Ch == Door || pp.Flags&(FReal|FPass) == (FReal|FPass)
+	return pp.Ch == Door || pp.Flags&(FReal|FPassage) == (FReal|FPassage)
 }
 
 // turnref decides whether to refresh at a passage turning (move.c turnref).
@@ -179,7 +179,7 @@ func (g *RogueGame) turnref() {
 // doorOpen is called to wake up things in a room that might move when the
 // hero enters (move.c door_open).
 func (g *RogueGame) doorOpen(rp *Room) {
-	if rp.Flags.Has(IsGone) {
+	if rp.Flags.Has(Gone) {
 		return
 	}
 	for y := rp.Pos.Y; y < rp.Pos.Y+rp.Max.Y; y++ {
@@ -194,24 +194,24 @@ func (g *RogueGame) doorOpen(rp *Room) {
 // beTrapped makes him pay for stepping on a trap (move.c be_trapped).
 func (g *RogueGame) beTrapped(tc Coord) int {
 	p := &g.Player
-	if p.On(IsLevit) {
-		return TRust // anything that's not a door or teleport
+	if p.On(Levitating) {
+		return TrapRust // anything that's not a door or teleport
 	}
 	g.Running = false
 	g.Count = 0
 	pp := g.Level.At(tc.Y, tc.X)
 	pp.Ch = Trap
-	tr := int(pp.Flags & FTMask)
+	tr := int(pp.Flags & FTrapMask)
 	pp.Flags.Set(FSeen)
 	switch tr {
-	case TDoor:
+	case TrapDoor:
 		g.Depth++
 		g.NewLevel()
 		g.msg("you fell into a trap!")
-	case TBear:
+	case TrapBear:
 		g.NoMove += g.spread(3) // BEARTIME
 		g.msg("you are caught in a bear trap")
-	case TMyst:
+	case TrapMystery:
 		switch g.rnd(11) {
 		case 0:
 			g.msg("you are suddenly in a parallel dimension")
@@ -236,11 +236,11 @@ func (g *RogueGame) beTrapped(tc Coord) int {
 		case 10:
 			g.msg("you pack turns %s!", rainbow[g.rnd(len(rainbow))])
 		}
-	case TSleep:
+	case TrapSleep:
 		g.NoCommand += g.spread(5) // SLEEPTIME
-		p.Flags.Clear(IsRun)
+		p.Flags.Clear(Awake)
 		g.msg("a strange white mist envelops you and you fall asleep")
-	case TArrow:
+	case TrapArrow:
 		if g.swing(p.Stats.Lvl-1, p.Stats.Arm, 1) {
 			p.Stats.HP -= g.roll(1, 6)
 			if p.Stats.HP <= 0 {
@@ -251,18 +251,18 @@ func (g *RogueGame) beTrapped(tc Coord) int {
 			}
 		} else {
 			arrow := newObject()
-			g.initWeapon(arrow, Arrow)
+			g.initWeapon(arrow, WeaponArrow)
 			arrow.Count = 1
 			arrow.Pos = p.Pos
 			g.fall(arrow, false)
 			g.msg("an arrow shoots past you")
 		}
-	case TTelep:
+	case TrapTeleport:
 		// since the hero's leaving, look() won't put a TRAP down for us,
 		// so we have to do it ourself
 		g.teleport()
 		g.mvaddch(tc.Y, tc.X, Trap)
-	case TDart:
+	case TrapDart:
 		if !g.swing(p.Stats.Lvl+1, p.Stats.Arm, 1) {
 			g.msg("a small dart whizzes by your ear and vanishes")
 		} else {
@@ -271,12 +271,12 @@ func (g *RogueGame) beTrapped(tc Coord) int {
 				g.msg("a poisoned dart killed you")
 				g.death('d')
 			}
-			if !p.IsWearing(RSustStr) && !g.save(VsPoison) {
+			if !p.IsWearing(RingSustainStrength) && !g.save(VsPoison) {
 				g.chgStr(-1)
 			}
 			g.msg("a small dart just hit you in the shoulder")
 		}
-	case TRust:
+	case TrapRust:
 		g.msg("a gush of water hits you on the head")
 		g.rustArmor(p.CurArmor)
 	}
@@ -311,7 +311,7 @@ func (g *RogueGame) rndmove(who *Creature) Coord {
 				break
 			}
 		}
-		if found != nil && found.Which == SScare {
+		if found != nil && found.Which == ScrollScareMonster {
 			return who.Pos
 		}
 	}
@@ -321,12 +321,12 @@ func (g *RogueGame) rndmove(who *Creature) Coord {
 // rustArmor rusts the given armor, if it is a legal kind to rust, and we
 // aren't wearing a magic ring (move.c rust_armor).
 func (g *RogueGame) rustArmor(arm *Object) {
-	if arm == nil || arm.Type != Armor || arm.Which == Leather ||
+	if arm == nil || arm.Type != Armor || arm.Which == ArmorLeather ||
 		arm.Arm >= 9 {
 		return
 	}
 
-	if arm.Flags.Has(IsProt) || g.Player.IsWearing(RSustArm) {
+	if arm.Flags.Has(Protected) || g.Player.IsWearing(RingMaintainArmor) {
 		if !g.ToDeath {
 			g.msg("the rust vanishes instantly")
 		}