Random events: earthquakes, overflowing rivers, new gold veins (free games and versus, can be switched off)

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

lang/en.lang

@@ -246,6 +246,7 @@ set.lights = Light sources
 set.ui_scale = Interface size
 set.game_speed = Game speed
 set.hints = Hints
+set.events = Random events
 set.keys_hint = Click an action and press a key. Keys already in use are swapped.
 set.press_key = Press a key for: {0}
 set.esc_cancel = Esc cancels
@@ -340,6 +341,10 @@ info.tortured = being tortured
 info.prison = Prisoners: {0}/{1}
 
 msg.wave_warn_dir = Scouts report: hero wave {0} reaches the gate in 30 seconds! They plan to break in from the {1}.
+msg.event_quake = Earthquake! Tunnels in the {0} have caved in.
+msg.event_lava = The lava overflows its banks in the {0}!
+msg.event_flood = Flood! The river overflows its banks in the {0}.
+msg.event_vein = The imps report a new gold vein in the {0}!
 msg.wave_warn_two = Scouts report: hero wave {0} reaches the gate in 30 seconds! They split up and break in from the {1} and the {2}.
 dir.n = north
 dir.ne = north-east