fix(simulation): discard movement input while paused

process_player_input processed movement commands regardless of tick
rate, causing the camera to drift from the player when the game was
paused and the player held direction keys. Add PlayerAction::is_movement()
helper and a paused guard that skips movement actions while TickRate is
Paused. Pause/Unpause commands still process normally.

Fixes bug #3 (player moves while game is paused).

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

server/src/bridge/types.rs

@@ -308,6 +308,23 @@ pub enum PlayerAction {
     ToggleStanceDown,
 }
 
+impl PlayerAction {
+    /// Returns true for directional movement commands.
+    pub fn is_movement(&self) -> bool {
+        matches!(
+            self,
+            PlayerAction::MoveNorth
+                | PlayerAction::MoveSouth
+                | PlayerAction::MoveEast
+                | PlayerAction::MoveWest
+                | PlayerAction::MoveNortheast
+                | PlayerAction::MoveNorthwest
+                | PlayerAction::MoveSoutheast
+                | PlayerAction::MoveSouthwest
+        )
+    }
+}
+
 /// Available interaction verbs for a nearby entity (D-060, #404)
 /// Embedded in ObserverSnapshot.nearby_interactions.
 #[derive(Debug, Clone, Serialize, Deserialize)]