feat: add live replays and PostgreSQL maintenance tools

- Stream compact live replay updates across local and clustered dashboards.
- Render responsive snake bodies as SVG paths with aligned custom icons.
- Add cache-busted assets, replay fallback routes, and live-follow playback.
- Support PostgreSQL benchmark sampling and idempotent SQLite migration.
- Add dry-run cleanup for old low-quality PostgreSQL replay payloads.
- Reward safe perimeter lanes and bump Prism to version 1.5.0.
- Add backend, migration, dashboard, and perimeter regression coverage.

tests/test_DashboardReplayRoute.py

@@ -0,0 +1,49 @@
+import os
+import unittest
+from unittest.mock import AsyncMock
+
+from server.Server import Server
+
+REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+REPLAY = {
+  'game': {'game_id': 'game-1', 'width': 11, 'height': 11},
+  'turns': [{'turn': 0, 'snakes': []}],
+}
+
+class TestDashboardReplayRoute(unittest.IsolatedAsyncioTestCase):
+  """The dashboard falls back to this route when the replay websocket is down."""
+
+  def setUp(self):
+    self.server = Server(
+      data_path=REPO_ROOT,
+      snake_type='PrismBattleSnake',
+      storage_type='memory',
+      metrics_backend='memory',
+      gameplay_db_enabled=False,
+    )
+    self.database = AsyncMock()
+    self.server.dashboard_query.gameplay_database = self.database
+
+  async def test_serves_replay_payload(self):
+    self.database.get_game_replay.return_value = dict(REPLAY)
+
+    response = await self.server.app.test_client().get('/dashboard/game/game-1')
+
+    self.assertEqual(response.status_code, 200)
+    payload = await response.get_json()
+    self.assertEqual(payload['game']['game_id'], 'game-1')
+    self.assertEqual(len(payload['turns']), 1)
+    self.database.get_game_replay.assert_awaited_once_with('game-1')
+
+  async def test_unknown_game_returns_404(self):
+    self.database.get_game_replay.return_value = None
+
+    response = await self.server.app.test_client().get('/dashboard/game/nope')
+
+    self.assertEqual(response.status_code, 404)
+    payload = await response.get_json()
+    self.assertEqual(payload['error'], 'game_not_found')
+
+if __name__ == '__main__':
+  unittest.main()