Runtime hygiene: fix RefCounted cycles (clean suite exit), full-length shifts, wand cooldown

- FSM holds owner via WeakRef; ShiftCoordinator is RefCounted (logic-only);
  persistence tests free the Save node -> test suite exits with zero
  'resources still in use' warnings (was ~13) and 57/57 pass
- GameManager uses each scenario's shift_duration_s (900s ~ 10-15 min) for
  real shifts instead of the 300s test duration
- Wand screening gets a 0.8s recharge cooldown with a wand.recharge message
- TODO/DONE/MEMORY/README synced

src/test/tests/test_strings.gd

@@ -30,7 +30,7 @@ func test_strings_cover_ui_keys() -> bool:
 		"hud.aim_first", "hud.no_one_nearby", "hud.targeting", "hud.no_wand",
 		"hud.screen_first", "access.granted", "access.denied", "access.policy_satisfied",
 		"access.wrong_grant", "access.wrong_deny", "wand.admitted_prohibited",
-		"wand.denied_false_alarm", "wand.cleared", "wand.refused", "radio.address_first",
+		"wand.denied_false_alarm", "wand.cleared", "wand.refused", "wand.recharge", "radio.address_first",
 		"radio.blocked", "radio.inaccurate", "radio.received", "radio.emergency_dispatched",
 		"responder.arrived", "react.comply", "react.leave", "react.argue", "react.record",
 		"react.ignore", "react.threaten", "react.force_entry", "react.return_later",