feat(testing): add deterministic mechanics capture

Add named launcher, flipper, and claw scenarios that advance at exact 120 Hz steps with stable seeds. Emit per-step JSON state/event traces and optionally capture the logical 640x460 framebuffer at any requested time or step.

Cover parser behavior, deterministic replay, launcher timing, flipper edges, and complete capture/release/idle cycles for all claw terminals.

Test Plan:
- cargo fmt --check
- cargo test
- cargo clippy --all-targets --all-features -- -D warnings
- cargo run -- --simulate claw-6 --at 0.15 --screenshot /tmp/tdkpin-sim-validation/claw-6-after-flush.png --trace /tmp/tdkpin-sim-validation/claw-6.json
- Inspect both generated 640x460 PNGs and JSON traces
- git diff --cached --check

tdkpin-rs/src/game.rs

@@ -193,7 +193,7 @@ impl Default for Ball {
     }
 }
 
-#[derive(Debug)]
+#[derive(Clone, Debug)]
 pub struct Game {
     pub players: Vec<Player>,
     pub current_player: usize,
@@ -275,6 +275,15 @@ impl Game {
         true
     }
 
+    pub(crate) fn begin_claw_scenario(&mut self, terminal_frame: u8) -> Vec<Event> {
+        self.ball.in_launcher = false;
+        self.ball.position = CLAW_TRIGGER_CENTER;
+        self.ball.velocity = Vec2::ZERO;
+        let mut events = Vec::new();
+        self.begin_claw_capture(terminal_frame, &mut events);
+        events
+    }
+
     fn fire_launcher(&mut self) {
         let launch_speed = LAUNCH_SPEED_MIN + self.launcher_charge * LAUNCH_SPEED_RANGE;
         self.ball.in_launcher = false;