Author the missing scenario content from the PLAN lists

Joke Shop
- Reservation list without ID (guest list valid, ID missing) — denied.
- Borrowed/mismatched ID (ID valid but mismatched) — denied.
- Guest who refuses the wand screen: new `refuses_screening` event flag, copied
  onto NPCController, handled in _toggle_wand_screening (logs wand.refused, records
  a wand_refused event, small prop hit, panel stays closed).
- Late arrival during the performance (ID + ticket, "arrive" intent).

Studio
- Filming-boundary event and a later repeat, both using the new `film_boundary`
  intent which maps to `steps_end` so the influencer stands past the posted line.
- Celebrity arrival now pulls in a small crowd via a new `extra_spawns` event field
  (two tourists + an influencer), spawned through the normal path.

Building
- Filming-boundary event whose hint points at the body camera and request-reason
  verbs, plus an unclear-intent event that hints at asking for a reason.

Engine support
- Events may carry `hint` (string key logged on spawn), `extra_spawns`, and
  `refuses_screening`; 9 new localized hint strings.

Tests/docs
- Headless suite 139 -> 149 (test_scenario_content.gd) and a new
  smoke_scenario_content.gd that spawns the refusal and celebrity events through the
  real signal path.
- README, TODO section moved to DONE, MEMORY. Version 0.2.13.

src/core/venue_scenario.gd

@@ -63,7 +63,9 @@ func _spot_for_intent(intent: String) -> String:
 			return "entrance"
 		"photo", "film", "perform", "wander", "roam":
 			return "sidewalk"
-		"sit":
+		"sit", "film_boundary":
+			# film_boundary: an influencer ignoring the posted filming line, so they
+			# stand at the steps instead of the permitted sidewalk spot.
 			return "steps_end"
 		_:
 			return "sidewalk"