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/pack.go

@@ -15,10 +15,10 @@ func (g *RogueGame) addPack(obj *Object, silent bool) {
 	}
 
 	// Check for and deal with scare monster scrolls
-	if obj.Type == Scroll && obj.Which == SScare && obj.Flags.Has(ObjIsFound) {
+	if obj.Type == Scroll && obj.Which == ScrollScareMonster && obj.Flags.Has(WasFound) {
 		detachObj(&g.Level.Objects, obj)
 		g.mvaddch(p.Pos.Y, p.Pos.X, g.floorCh())
-		if p.Room.Flags.Has(IsGone) {
+		if p.Room.Flags.Has(Gone) {
 			g.Level.SetChar(p.Pos.Y, p.Pos.X, Passage)
 		} else {
 			g.Level.SetChar(p.Pos.Y, p.Pos.X, Floor)
@@ -101,7 +101,7 @@ func (g *RogueGame) addPack(obj *Object, silent bool) {
 		}
 	}
 
-	obj.Flags.Set(ObjIsFound)
+	obj.Flags.Set(WasFound)
 
 	// If this was the object of something's desire, that monster will get
 	// mad and run at the hero.
@@ -146,7 +146,7 @@ func (g *RogueGame) packRoom(fromFloor bool, obj *Object) bool {
 	if fromFloor {
 		detachObj(&g.Level.Objects, obj)
 		g.mvaddch(p.Pos.Y, p.Pos.X, g.floorCh())
-		if p.Room.Flags.Has(IsGone) {
+		if p.Room.Flags.Has(Gone) {
 			g.Level.SetChar(p.Pos.Y, p.Pos.X, Passage)
 		} else {
 			g.Level.SetChar(p.Pos.Y, p.Pos.X, Floor)
@@ -234,7 +234,7 @@ func (g *RogueGame) inventory(list []*Object, typ int) bool {
 // pickUp adds something to the character's pack (pack.c pick_up).
 func (g *RogueGame) pickUp(ch byte) {
 	p := &g.Player
-	if p.On(IsLevit) {
+	if p.On(Levitating) {
 		return
 	}
 
@@ -348,7 +348,7 @@ func (g *RogueGame) money(value int) {
 	p := &g.Player
 	p.Purse += value
 	g.mvaddch(p.Pos.Y, p.Pos.X, g.floorCh())
-	if p.Room.Flags.Has(IsGone) {
+	if p.Room.Flags.Has(Gone) {
 		g.Level.SetChar(p.Pos.Y, p.Pos.X, Passage)
 	} else {
 		g.Level.SetChar(p.Pos.Y, p.Pos.X, Floor)
@@ -364,7 +364,7 @@ func (g *RogueGame) money(value int) {
 // floorCh returns the appropriate floor character for her room
 // (pack.c floor_ch).
 func (g *RogueGame) floorCh() byte {
-	if g.Player.Room.Flags.Has(IsGone) {
+	if g.Player.Room.Flags.Has(Gone) {
 		return Passage
 	}
 	if g.showFloor() {