fix(physics): gate dynamic impulse on capture age

Match records 174/175 by transferring normal impulse only when the other slot capture age is nonpositive. A held slot now keeps its velocity and the moving ball resolves with the full normal velocity; successful transfer retains the original normal_velocity-1000 response.

Test Plan:
- cargo test --all-targets
- cargo clippy --all-targets --all-features -- -D warnings
- rumdl check CHANGELOG.md RECONSTRUCTION.md README.md
- git diff --check

tdkpin-rs/src/game.rs

@@ -749,6 +749,7 @@ impl Game {
                 ball.spin,
                 other_position,
                 MilliVec::from_velocity_per_second(secondary.velocity),
+                secondary.capture_age <= 0,
             );
             if predicted.x >= other_position.x.wrapping_sub(21_000)
                 && predicted.x <= other_position.x.wrapping_add(21_000)
@@ -1140,6 +1141,7 @@ impl Game {
         };
         let primary_position = self.ball.position;
         let primary_velocity = self.ball.velocity;
+        let primary_capture_age = self.ball.capture_age;
         let old_position = MilliVec::from_position(ball.position);
         let mut velocity = MilliVec::from_velocity_per_second(ball.velocity);
         velocity.y += GRAVITY_MILLI_PER_STEP;
@@ -1173,6 +1175,7 @@ impl Game {
                 ball.spin,
                 other_position,
                 MilliVec::from_velocity_per_second(primary_velocity),
+                primary_capture_age <= 0,
             )
             && best_collision.is_none()
         {

tdkpin-rs/src/original_physics.rs

@@ -549,6 +549,7 @@ pub fn ball_collision_response(
     spin: Real48,
     other_position: MilliVec,
     other_velocity: MilliVec,
+    transfer_enabled: bool,
 ) -> Option<BallCollisionResponse> {
     let mut surface_distance =
         milli_distance(subtract(other_position, old_position)).wrapping_sub(17_000);
@@ -574,24 +575,32 @@ pub fn ball_collision_response(
         return None;
     }
     surface_distance = surface_distance.wrapping_add(3_000);
-    let transfer_x = Real48::from_i32(collision_velocity)
-        .multiply(normal_y)
-        .divide(Real48::from_i32(length))
-        .round_i32();
-    let transfer_y = Real48::from_i32(collision_velocity)
-        .multiply(normal_x)
-        .divide(Real48::from_i32(length))
-        .round_i32();
-    let other_velocity = MilliVec {
-        x: other_velocity.x.wrapping_add(transfer_x),
-        y: other_velocity.y.wrapping_sub(transfer_y),
+    let other_velocity = if transfer_enabled {
+        let transfer_x = Real48::from_i32(collision_velocity)
+            .multiply(normal_y)
+            .divide(Real48::from_i32(length))
+            .round_i32();
+        let transfer_y = Real48::from_i32(collision_velocity)
+            .multiply(normal_x)
+            .divide(Real48::from_i32(length))
+            .round_i32();
+        MilliVec {
+            x: other_velocity.x.wrapping_add(transfer_x),
+            y: other_velocity.y.wrapping_sub(transfer_y),
+        }
+    } else {
+        other_velocity
     };
     let (moving_velocity, moving_spin, _) = apply_response(
         velocity,
         spin,
         normal_x,
         normal_y,
-        collision_velocity.wrapping_sub(1_000),
+        if transfer_enabled {
+            collision_velocity.wrapping_sub(1_000)
+        } else {
+            collision_velocity
+        },
         CollisionMaterial::circle(0.9, 0.0, 0.0).real48(),
     );
     Some(BallCollisionResponse {
@@ -930,11 +939,30 @@ mod tests {
                 y: 100_000,
             },
             MilliVec::default(),
+            true,
         )
         .expect("moving ball enters the 17-pixel dynamic record");
         assert_eq!(response.surface_distance, 4_000);
         assert_eq!(response.other_velocity, MilliVec { x: 3_000, y: 0 });
         assert_eq!(response.moving_velocity, MilliVec { x: -4_600, y: 0 });
         assert_eq!(response.moving_spin, Real48::ZERO);
+
+        let held_other = ball_collision_response(
+            MilliVec {
+                x: 100_000,
+                y: 100_000,
+            },
+            MilliVec { x: 3_000, y: 0 },
+            Real48::ZERO,
+            MilliVec {
+                x: 118_000,
+                y: 100_000,
+            },
+            MilliVec::default(),
+            false,
+        )
+        .expect("the held slot still presents a dynamic collision record");
+        assert_eq!(held_other.other_velocity, MilliVec::default());
+        assert_eq!(held_other.moving_velocity, MilliVec { x: -2_700, y: 0 });
     }
 }