fix(simulation): correct tick synchronization in snapshot generation

Snapshot for tick N should show state at END of tick N. Reorder systems
so generate_snapshot runs after validate_movement but before
advance_tick. Previously snapshot.tick was the incremented tick,
not the tick whose inputs were processed. Also fix main.rs accept
error to log address context before exiting.

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

server/src/simulation/mod.rs

@@ -24,8 +24,8 @@ impl Plugin for SimulationPlugin {
                 Update,
                 (
                     input::process_player_input,
-                    time::advance_tick.after(input::process_player_input),
-                    movement::validate_movement.after(time::advance_tick),
+                    movement::validate_movement.after(input::process_player_input),
+                    time::advance_tick.after(movement::validate_movement),
                 ),
             );