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/rings.go

@@ -48,11 +48,11 @@ func (g *RogueGame) ringOn() {
 
 	// Calculate the effect it has on the poor guy.
 	switch obj.Which {
-	case RAddStr:
+	case RingAddStrength:
 		g.chgStr(obj.Arm)
-	case RSeeInvis:
+	case RingSeeInvisible:
 		g.invisOn()
-	case RAggr:
+	case RingAggravateMonsters:
 		g.aggravate()
 	}
 
@@ -123,7 +123,7 @@ func (g *RogueGame) gethand() int {
 
 // ringUses is the rings.c ring_eat static uses[] table: how much food each
 // ring type uses up per turn (negative = a 1-in-n chance of 1).
-var ringUses = [MaxRings]int{
+var ringUses = [NumRingTypes]int{
 	1,  // R_PROTECT
 	1,  // R_ADDSTR
 	1,  // R_SUSTSTR
@@ -155,7 +155,7 @@ func (g *RogueGame) ringEat(hand int) int {
 			eat = 0
 		}
 	}
-	if ring.Which == RDigest {
+	if ring.Which == RingSlowDigestion {
 		eat = -eat
 	}
 	return eat
@@ -163,11 +163,11 @@ func (g *RogueGame) ringEat(hand int) int {
 
 // ringNum prints ring bonuses (rings.c ring_num).
 func ringNum(g *RogueGame, obj *Object) string {
-	if !obj.Flags.Has(IsKnow) {
+	if !obj.Flags.Has(Known) {
 		return ""
 	}
 	switch obj.Which {
-	case RProtect, RAddStr, RAddDam, RAddHit:
+	case RingProtection, RingAddStrength, RingIncreaseDamage, RingDexterity:
 		return fmt.Sprintf(" [%s]", num(obj.Arm, 0, Ring))
 	}
 	return ""