Export venues as editor-authorable .tres resources

- tools/export_venues.gd (SceneTree script) saves the three factory scenarios to
  content/venues/<id>.tres via ResourceSaver. The factory stays the source of truth;
  the exported files are what an editor workflow would edit and ship.
- New tests load the files back and check that id, name, event pool, profiles,
  policy (ID/wand), equipment, door-staff lines, shift phases, and locations all
  survive. They also fail when the exported files are missing or stale, so the
  export is re-run after content changes.
- GUT is consciously not adopted: the custom headless runner already covers 157
  assertions without an editor plugin and keeps CI dependency-free. Recorded in
  DONE.md.
- TODO: the planned backlog is complete; only optional future ideas remain.
- README/MEMORY updated. Version 0.2.16.

tools/export_venues.gd

@@ -0,0 +1,26 @@
+extends SceneTree
+## Export the built-in scenarios to `.tres` resources for editor authoring.
+##
+## Usage:
+##   godot --headless --path . --script res://tools/export_venues.gd
+##
+## Writes content/venues/<id>.tres. These mirror ScenarioFactory exactly; the
+## factory stays the source of truth for the prototype, and the exported files are
+## what an editor-based workflow would edit and ship.
+
+const Factory := preload("res://src/content/scenario_factory.gd")
+
+func _initialize() -> void:
+	var out_dir := "res://content/venues"
+	DirAccess.make_dir_recursive_absolute(out_dir)
+	var scenarios := [Factory.hollywood_building(), Factory.joke_shop(), Factory.tv_studio()]
+	var failures := 0
+	for scenario in scenarios:
+		var path := "%s/%s.tres" % [out_dir, scenario.id]
+		var err: int = ResourceSaver.save(scenario, path)
+		if err == OK:
+			print("wrote %s" % path)
+		else:
+			printerr("failed to write %s (error %d)" % [path, err])
+			failures += 1
+	quit(0 if failures == 0 else 1)