P14-03: Price whole-shaft elevator waits in A* route choice

Riders queued for any floor pair in a shaft now delay every pair: the
elevator service publishes the rest of the shaft queue as each connector's
dynamic cost, refreshed on trip changes and each cabin minute, and restore
rejects saves whose wait disagrees with their trips. A two-shaft fixture with
real guests shows rush diversion, shared cabins within capacity, recovery,
route loss and warp-exit congestion.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/world/path_service.gd

@@ -395,6 +395,27 @@ func set_connector_enabled(connector_id: StringName, enabled: bool) -> bool:
 	return true
 
 
+## Cost-only update (no topology change), e.g. waiting riders elsewhere in the
+## same elevator shaft. Any change may make routes cheaper, so all caches drop.
+func set_connector_dynamic_cost(connector_id: StringName, dynamic_cost: int) -> bool:
+	if not _connectors.has(connector_id):
+		last_error = "Unknown connector id: %s" % connector_id
+		return false
+	if dynamic_cost < 0:
+		last_error = "Connector dynamic cost must be non-negative."
+		return false
+	var connector: Dictionary = _connectors[connector_id]
+	if int(connector[&"dynamic_cost"]) == dynamic_cost:
+		last_error = ""
+		return true
+	connector[&"dynamic_cost"] = dynamic_cost
+	_connectors[connector_id] = connector
+	traffic_revision += 1
+	invalidate_all_cache()
+	last_error = ""
+	return true
+
+
 func set_connector_operational_state(connector_id: StringName, state: StringName) -> bool:
 	if not _connectors.has(connector_id):
 		last_error = "Unknown connector id: %s" % connector_id