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/fight.go

@@ -47,7 +47,7 @@ func (g *RogueGame) fight(mp Coord, weap *Object, thrown bool) bool {
 	// place.
 	g.Count = 0
 	g.Quiet = 0
-	g.runto(mp)
+	g.runTo(mp)
 	// Let him know it was really a xeroc (if it was one).
 	if tp.Type == 'X' && tp.Disguise != 'X' && !p.On(Blind) {
 		tp.Disguise = 'X'
@@ -182,7 +182,7 @@ func (g *RogueGame) attack(mp *Monster) int {
 				// Rattlesnakes have poisonous bites
 				if !g.save(VsPoison) {
 					if !p.IsWearing(RingSustainStrength) {
-						g.chgStr(-1)
+						g.changeStrength(-1)
 
 						if !g.Options.Terse {
 							g.msg("you feel a bite in your leg and now feel weaker")