feat(client): character select, triangle activation consumer, news ticker

Sprint 24 Signal — three client tickets delivering the player-facing
storyteller feedback loop:

- #588: Character archetype select screen between New Game and session
  start. Two-card UI (Smuggler/Detective), keyboard+mouse, ESC cancels.
  GameState.character_archetype persisted and sent in StartupMessage.
  PROTOCOL_VERSION bumped to 19.
- #590: Triangle crisis event consumer. Decodes triangle_crisis_events
  from snapshot, fires sfx_monologue_chime_urgent once per triangle per
  session via AudioManager.CHIME_ACTIVATION.
- #592: News ticker HUD element. Scrolling marquee on UILayer, visible
  only when current_ticker is present in snapshot (Last Shift zone).
  Zero-arg update_from_state reads from GameState.current_snapshot.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/scripts/protocol/protocol.gd

@@ -11,7 +11,8 @@ class_name Protocol
 
 ## Protocol version — must match server PROTOCOL_VERSION in bridge/types.rs.
 ## Reject snapshots where version != this value.
-const PROTOCOL_VERSION: int = 18
+## v19: adds character_archetype field to StartupMessage (#588, #587).
+const PROTOCOL_VERSION: int = 19
 
 
 # -- Decode: bytes from server → GDScript types --------------------------------
@@ -255,6 +256,28 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 			"success": bool(raw_debug.get("success", false)),
 		}
 
+	# v19: triangle_crisis_events (#590, D-072/D-089) — one-shot activation events.
+	# Each entry: {triangle_id: int}. Client deduplicates by triangle_id across ticks.
+	var triangle_crisis_events: Array = []
+	var raw_tce: Variant = raw.get("triangle_crisis_events")
+	if raw_tce is Array:
+		for raw_ev in raw_tce:
+			if raw_ev is Dictionary and raw_ev.has("triangle_id"):
+				triangle_crisis_events.append({
+					"triangle_id": int(raw_ev["triangle_id"]),
+				})
+
+	# v19: current_ticker (#592) — scrolling news headline when in The Last Shift zone.
+	# {id: String, text: String, category: String} or null when player outside bar zone.
+	var current_ticker: Variant = null
+	var raw_ticker: Variant = raw.get("current_ticker")
+	if raw_ticker is Dictionary and raw_ticker.has("text"):
+		current_ticker = {
+			"id": str(raw_ticker.get("id", "")),
+			"text": str(raw_ticker["text"]),
+			"category": str(raw_ticker.get("category", "")),
+		}
+
 	# TODO(server): Send stationary_ticks in ObserverSnapshot (D-071, D-020).
 	# Server already tracks this in ListeningFocus component (server/src/simulation/listening.rs).
 	# When server populates this field, client-side accumulation fallback in game_state.gd
@@ -334,6 +357,8 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 		"debug_response": debug_response,
 		"stationary_ticks": stationary_ticks,
 		"zone_id": zone_id,
+		"triangle_crisis_events": triangle_crisis_events,
+		"current_ticker": current_ticker,
 	}
 
 
@@ -439,11 +464,17 @@ static func _decode_enum_variant(raw) -> Dictionary:
 
 # -- Encode: GDScript types → bytes to server ----------------------------------
 
-## Encode a StartupMessage to MessagePack bytes (#175).
+## Encode a StartupMessage to MessagePack bytes (#175, #588).
 ## Sent by the client immediately after handshake validation.
-## Server reads this to initialize SimRng with the world seed (D-010, D-029).
-static func encode_startup_message(world_seed: int) -> PackedByteArray:
-	var msg := {"world_seed": world_seed}
+## Server reads this to initialize SimRng (D-010, D-029) and select monologue pool (D-032).
+## character_archetype: "detective" → "Detective", "smuggler" → "Smuggler" (server enum variant).
+static func encode_startup_message(world_seed: int, character_archetype: String = "detective") -> PackedByteArray:
+	# Map client lowercase archetype string to server PascalCase enum variant.
+	var archetype_variant: String = character_archetype.capitalize()
+	var msg := {
+		"world_seed": world_seed,
+		"character_archetype": archetype_variant,
+	}
 	var result = Messagepack.encode(msg)
 	if result.status != null:
 		push_error("Protocol: startup message encode failed: %s" % result.status)