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/passages.go

@@ -246,6 +246,38 @@ func (g *RogueGame) door(rm *Room, cp Coord) {
 	}
 }
 
+// addPass adds the passages to the current window — wizard command
+// (passages.c add_pass).
+func (g *RogueGame) addPass() {
+	for y := 1; y < NumLines-1; y++ {
+		for x := 0; x < NumCols; x++ {
+			pp := g.Level.At(y, x)
+			if pp.Flags.Has(FPass) || pp.Ch == Door ||
+				(!pp.Flags.Has(FReal) && (pp.Ch == '|' || pp.Ch == '-')) {
+				ch := pp.Ch
+				if pp.Flags.Has(FPass) {
+					ch = Passage
+				}
+				pp.Flags.Set(FSeen)
+				g.move(y, x)
+				if pp.Monst != nil {
+					pp.Monst.OldCh = pp.Ch
+				} else if pp.Flags.Has(FReal) {
+					g.addch(ch)
+				} else {
+					g.standout()
+					if pp.Flags.Has(FPass) {
+						g.addch(Passage)
+					} else {
+						g.addch(Door)
+					}
+					g.standend()
+				}
+			}
+		}
+	}
+}
+
 // passnum assigns a number to each passageway (passages.c passnum).
 func (g *RogueGame) passnum() {
 	g.pnum = 0