Convert doZap to a per-wand handler table (refactor step 7)

The do_zap switch becomes gameData.zapHandlers, indexed by WandKind;
the shared monster-ray preamble is zapRayMonster/zapVictim, teleport
away/to and the three bolt wands share handlers, and a false return
aborts the zap without spending a charge (drain life on a too-weak
hero, as in C). Effect order and RNG call sequence unchanged.

game/tables.go

@@ -132,6 +132,11 @@ type gameData struct {
 	// the cases of the scrolls.c read_scroll switch. The handler gets
 	// the scroll being read (the identify family needs its subtype).
 	readHandlers [NumScrollTypes]func(g *RogueGame, obj *Object)
+
+	// zapHandlers dispatches each wand kind to its effect method: the
+	// cases of the sticks.c do_zap switch. A false return aborts the
+	// zap without using a charge (drain life on a too-weak hero).
+	zapHandlers [NumWandTypes]func(g *RogueGame, obj *Object) bool
 }
 
 // ripWall is the repeated blank wall line of the tombstone art.
@@ -635,6 +640,22 @@ func newGameData() *gameData {
 			ScrollAggravateMonsters:   (*RogueGame).readAggravateMonsters,
 			ScrollProtectArmor:        (*RogueGame).readProtectArmor,
 		},
+
+		zapHandlers: [NumWandTypes]func(*RogueGame, *Object) bool{
+			WandLight:        (*RogueGame).zapLight,
+			WandInvisibility: (*RogueGame).zapInvisibility,
+			WandLightning:    (*RogueGame).zapBolt,
+			WandFire:         (*RogueGame).zapBolt,
+			WandCold:         (*RogueGame).zapBolt,
+			WandPolymorph:    (*RogueGame).zapPolymorph,
+			WandMagicMissile: (*RogueGame).zapMagicMissile,
+			WandHasteMonster: (*RogueGame).zapSpeed,
+			WandSlowMonster:  (*RogueGame).zapSpeed,
+			WandDrainLife:    (*RogueGame).zapDrainLife,
+			WandTeleportAway: (*RogueGame).zapTeleport,
+			WandTeleportTo:   (*RogueGame).zapTeleport,
+			WandCancellation: (*RogueGame).zapCancellation,
+		},
 	}
 }