go: port command loop, save/restore, tcell terminal, and the binary

- command.c in full: the command dispatcher with repeat counts, run
  prefixes, ctrl-run door-stop mode, fight-to-death targeting, and all
  wizard debug commands; search, help, identify, d_level/u_level, call,
  current
- main.c completed: Run()/playit() with the C double ROGUEOPTS parse;
  exit()-anywhere becomes a gameEnd panic recovered in Run
- save.c + state.c: gob SaveState snapshot with explicit pointer-to-
  index fixups for equipment, monster rooms, and chase targets (the
  rs_fix_thing role); save file deleted on restore as in C; SIGHUP/
  SIGTERM autosave hook
- wizard.c completed (create_obj, show_map), passages.c add_pass
- term/: tcell/v2 Terminal — the one third-party dependency — replacing
  curses and mdport's 900-line key decoder; shell escape via suspend
- cmd/rogue: flags -s/-d, SEED (wizard), ROGUEOPTS, ROGUE_WIZARD

Tests: full scripted sessions through Run (quit, descend stairs,
3200-move crash sweep, save-command round trip). Notable fixes found
by tests: gob silently drops embedded fields of unexported types, and
--More-- prompts swallow space-free input scripts.

game/level.go

@@ -50,23 +50,6 @@ func (l *Level) VisibleChar(y, x int) byte {
 	return l.Char(y, x)
 }
 
-// reset clears the per-level state ahead of NewLevel drawing a fresh level.
-func (l *Level) reset() {
-	for i := range l.Places {
-		l.Places[i] = Place{}
-	}
-	for i := range l.Rooms {
-		l.Rooms[i] = Room{}
-	}
-	for i := range l.Passages {
-		l.Passages[i] = Room{Flags: IsGone | IsDark}
-	}
-	l.Objects = nil
-	l.Monsters = nil
-	l.Stairs = Coord{}
-	l.NTraps = 0
-}
-
 // goldCalc is the GOLDCALC macro: how much a gold pile is worth at depth.
 func (g *RogueGame) goldCalc() int {
 	return g.rnd(50+10*g.Depth) + 2