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/npc_controller.gd

@@ -34,6 +34,8 @@ var guard_noticed := false
 
 ## Whether this NPC has passed the handheld wand screening (The Joke Shop).
 var screened := false
+## Authored event flag: this person refuses the wand screen (Joke Shop).
+var refuses_screening := false
 ## Whether the guard has declared they recognize this person (a player decision
 ## recorded as evidence, PLAN.md: Authorized Access).
 var player_recognized := false