feat: add Zenith strategy and move latency tracing

- Register Zenith 1.1 with balanced duel verdicts and forced-outcome overrides.
- Prioritize permanent-trail space in Constrictor and health-aware hazard routes.
- Deduct executor queue delays and return fallback directions on move timeouts.
- Correlate response headers, replay timings, and sampled structured trace logs.
- Move shared metrics publication off the response path without losing local counts.
- Allow configurable tournament opponents and add a psql helper recipe.
- Preserve empty latency values through compact replay encoding and migration.
- Update Arena game links and use default assets for missing customizations.
- Cover strategy, HTTP lifecycle, tracing, replay codecs, and dashboard behavior.
- Validate with 260 passing Python tests, 4 skips, and 2 passing JavaScript tests.

tests/test_BattlesnakeLifecycle.py

@@ -135,6 +135,58 @@ class TestBattlesnakeLifecycle(unittest.IsolatedAsyncioTestCase):
         self.assertNotEqual(replay['game']['status'], 'running')
         print(f'Real SQLite HTTP timings: {timings}')
 
+  async def test_timed_out_move_returns_valid_fallback(self):
+    server = self.server
+    server.logger = Mock()
+    server.logger.warning.return_value = None
+    server.game_lifecycle.turn = AsyncMock()
+    server.metrics_collector.record_move = AsyncMock()
+    state = deepcopy(self.state)
+    state['game']['timeout'] = 100
+
+    async def stalled_board(*args):
+      await asyncio.sleep(0.2)
+
+    server.game_runtime.get_game_board = stalled_board
+    response = await server.app.test_client().post('/move', json=state, headers=self.headers)
+    self.assertEqual(response.status_code, 200)
+    self.assertIn((await response.get_json())['move'], ('up', 'down', 'left', 'right'))
+    await server.game_lifecycle.drain()
+
+  async def test_slow_metrics_publish_is_off_response_path_and_traced(self):
+    server = self.server
+    gate = asyncio.Event()
+    snapshots = []
+
+    async def slow_publish():
+      await gate.wait()
+      await asyncio.sleep(0.1)
+
+    async def capture(state, move, thinking):
+      snapshots.append(thinking)
+
+    server.metrics_collector.publish_move_metrics = slow_publish
+    server.gameplay_tracking.record_gameplay_turn_snapshot = capture
+    server.dashboard_query.push_dashboard_game_replay_update = AsyncMock()
+    client = server.app.test_client()
+    started = perf_counter()
+    response = await asyncio.wait_for(client.post('/move', json=self.state, headers=self.headers), 0.5)
+    elapsed = (perf_counter() - started) * 1000
+    self.assertEqual(response.status_code, 200)
+    self.assertLess(elapsed, 500)
+    trace_id = response.headers['X-Move-Trace-ID']
+    self.assertEqual(len(trace_id), 32)
+    self.assertEqual(snapshots, [])
+    gate.set()
+    await server.game_lifecycle.drain()
+    trace = snapshots[0]['move_trace']
+    self.assertEqual(trace['trace_id'], trace_id)
+    self.assertGreaterEqual(trace['metrics_publish_ms'], 90)
+    self.assertIn('executor_queue_ms', trace)
+    self.assertIn('strategy_ms', trace)
+    self.assertIn('response_encode_ms', trace)
+    self.assertFalse(trace['timed_out'])
+
   async def test_invalid_agent_does_not_schedule_work(self):
     response = await self.server.app.test_client().post('/start', json=self.state)
     self.assertEqual(response.status_code, 404)