Rename movement/world methods to idiomatic Go; remove all gotos

Refactor step 4. Renames (C breadcrumbs kept in doc comments):
doMove→moveHero, beTrapped→springTrap, rndmove→randomStep,
doRooms→digRooms, doPassages→digPassages, doMaze→digMaze,
chgStr→changeStrength, doRun→startRun, moveStuff→finishMove,
turnref→turnRefresh, moveMonst→moveMonster, doChase→chaseStep,
setOldch→setOldChar, cansee→canSee, roomin→roomIn, runto→runTo,
conn→connectRooms, putpass→putPassage, passnum→numberPassages,
numpass→numberPassage, rndPos→randomPos, rndRoom→randomRoom,
treasRoom→treasureRoom, accntMaze→accountMaze.

All goto/label flows are gone: moveHero uses a retry loop with the
PASSGO corner logic extracted into passageTurn; dispatch re-dispatches
via a loop; chaseStep re-checks via a loop; saveGame uses a labeled
prompt loop. Control flow and RNG call order are unchanged; suite
green.

game/misc.go

@@ -305,9 +305,9 @@ func (g *RogueGame) checkLevel() {
 	}
 }
 
-// chgStr modifies the player's strength, keeping track of the highest it
-// has been (misc.c chg_str).
-func (g *RogueGame) chgStr(amt int) {
+// changeStrength modifies the player's strength, keeping track of the
+// highest it has been (misc.c chg_str).
+func (g *RogueGame) changeStrength(amt int) {
 	if amt == 0 {
 		return
 	}
@@ -362,10 +362,10 @@ func (g *RogueGame) addHaste(potion bool) bool {
 
 // aggravate aggravates all the monsters on this level (misc.c aggravate).
 func (g *RogueGame) aggravate() {
-	// runto() can splice the monster list while we walk it, so iterate a copy.
+	// runTo() can splice the monster list while we walk it, so iterate a copy.
 	monsters := append([]*Monster(nil), g.Level.Monsters...)
 	for _, mp := range monsters {
-		g.runto(mp.Pos)
+		g.runTo(mp.Pos)
 	}
 }