Implement TODO backlog: LATE phase fix, protester, CALL_SOMEONE, door lock, flashlight, persistence, navmesh, JSON localization, and release tooling

- Fix LATE shift phase (start 700s) so the violent-threat event is reachable
- Add PROTESTER archetype (rules, profile, colors, events in public venues)
- Add CALL_SOMEONE reaction (FSM -> ARGUING, influencer/trespasser/protester weights)
- Door lock: DoorState core class, L binding, red/green visual indicator,
  locked doors thwart FORCE_ENTRY
- Flashlight: G binding, SpotLight3D, perception radius bonus at evening/late
- Persistence: save shift results via Save autoload, history + best score on
  review screen, round-trip test
- Navigation: flat NavigationRegion3D navmesh, NavigationAgent3D path following
  with direct-movement fallback; steps made visual-only so NPCs reach entrance
- Localization: strings moved to content/strings.en.json (loader keeps
  lookup/fmt signatures; coverage test over all keys)
- Distribution: export_presets.cfg (Linux/Windows/macOS), tools/build_releases.sh,
  docs/RELEASING.md, prominent README Downloads section
- Remove stale signal_bus.gd (invalid static-signal experiment)
- Tests: 53 passing across 9 suites

src/test/tests/test_persistence.gd

@@ -0,0 +1,29 @@
+extends RefCounted
+## Headless tests for shift-result persistence (Save autoload, user:// JSON).
+
+func _save_instance() -> Object:
+	var save_script: GDScript = load("res://src/autoload/save.gd")
+	return save_script.new()
+
+func test_save_round_trip() -> bool:
+	var save := _save_instance()
+	var review := {
+		"scenario_id": "hollywood_building",
+		"reputation": {"rating": 82.5, "grade": "B"},
+		"spawned_count": 7,
+		"completed_at_ms": Time.get_ticks_msec(),
+	}
+	var err: int = save.save_shift_result(review)
+	var a := TestUtils.check_eq(err, OK, "save succeeds")
+	var results: Array = save.load_shift_results()
+	var b := TestUtils.check(results.size() > 0, "history non-empty after save")
+	var last: Dictionary = results[results.size() - 1]
+	var c := TestUtils.check_eq(last.get("scenario_id", ""), "hollywood_building", "round-trips scenario id")
+	var d := TestUtils.check_eq(float(last.get("reputation", {}).get("rating", 0.0)), 82.5, "round-trips rating")
+	return a and b and c and d
+
+func test_load_returns_array_when_empty_or_missing() -> bool:
+	# The tester home may already contain results; this only asserts shape safety.
+	var save := _save_instance()
+	var results: Array = save.load_shift_results()
+	return TestUtils.check(results is Array, "load_shift_results always returns Array")