Expand and stage boss encounter

core/GameState.gd

@@ -47,6 +47,10 @@ var catalog_faults: PackedStringArray = PackedStringArray()
 # set, so the fleet goes where the script sends it rather than fighting the
 # player for the last few seconds of the prologue.
 var intro_locks_movement: bool = false
+# Short in-world reveals (currently the boss arrival) use their own lock so
+# they do not pretend the prologue is active merely to steer the fleet for a
+# few seconds.
+var encounter_locks_movement: bool = false
 # #123: the prologue's convoy is bigger than any fleet the player can field
 # yet - it is not their fleet, it is the one they are about to lose. An
 # explicit override rather than a fake doctrine, so nothing about the
@@ -751,6 +755,7 @@ func reset_progression() -> void:
 func reset_new_game() -> void:
 	intro_active = true
 	intro_locks_movement = false
+	encounter_locks_movement = false
 	intro_fleet_size = 0
 	has_return_position = false
 	surviving_ship_count = STARTING_SHIP_COUNT