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_PostgresqlGameplayMigration.py

@@ -0,0 +1,65 @@
+import sqlite3
+import tempfile
+import unittest
+from pathlib import Path
+
+from server.database.backend.PostgresqlGameplayBackend import PostgresqlGameplayBackend
+
+class TestPostgresqlGameplayMigration(unittest.TestCase):
+  def _create_source(self, path:Path, winner_column:str, winner_value:str|None) -> None:
+    with sqlite3.connect(path) as connection:
+      connection.executescript(f"""
+        CREATE TABLE games (
+          game_id TEXT PRIMARY KEY, started_at TEXT NOT NULL, ended_at TEXT,
+          width INTEGER, height INTEGER, source TEXT, map_name TEXT,
+          ruleset_name TEXT, ruleset_version TEXT, your_snake_id TEXT,
+          your_snake_name TEXT, your_snake_type TEXT, your_snake_version TEXT,
+          game_type TEXT, {winner_column} TEXT, winner_you INTEGER,
+          final_turn INTEGER, status TEXT
+        );
+        CREATE TABLE turns (
+          game_id TEXT, turn INTEGER, observed_at TEXT, my_move TEXT,
+          my_thinking_json TEXT, board_state_json TEXT, snakes_json TEXT,
+          you_json TEXT, food_json TEXT, hazards_json TEXT
+        );
+        CREATE TABLE snake_turns (
+          game_id TEXT, turn INTEGER, snake_id TEXT, snake_name TEXT,
+          health INTEGER, length INTEGER, head_x INTEGER, head_y INTEGER,
+          body_json TEXT, is_you INTEGER, inferred_move TEXT, latency TEXT
+        );
+      """)
+      connection.execute(
+        f"""INSERT INTO games (
+          game_id, started_at, {winner_column}, winner_you, final_turn, status
+        ) VALUES (?, ?, ?, ?, ?, ?)""",
+        ("game-1", "2026-08-01T10:00:00+00:00", winner_value, 1, 4, "finished"),
+      )
+
+  def test_reads_current_winner_name_schema(self):
+    with tempfile.TemporaryDirectory() as temp_dir:
+      path = Path(temp_dir) / "gameplay.sqlite3"
+      self._create_source(path, "winner_name", "Prism")
+      backend = PostgresqlGameplayBackend("postgresql://example", sqlite_migration_path=str(path))
+
+      games, turns, snake_turns = backend._read_sqlite_data_sync(str(path))
+
+      self.assertEqual(games[0]["winner_name"], "Prism")
+      self.assertEqual(turns, [])
+      self.assertEqual(snake_turns, [])
+      self.assertEqual(backend._migrated_winner_name(games[0]["winner_name"]), "Prism")
+
+  def test_reads_legacy_winner_names_json_schema(self):
+    with tempfile.TemporaryDirectory() as temp_dir:
+      path = Path(temp_dir) / "gameplay.sqlite3"
+      self._create_source(path, "winner_names_json", '["Prism"]')
+      backend = PostgresqlGameplayBackend("postgresql://example", sqlite_migration_path=str(path))
+
+      games, _, _ = backend._read_sqlite_data_sync(str(path))
+
+      self.assertEqual(
+        backend._migrated_winner_name(games[0]["winner_name"]),
+        "Prism",
+      )
+
+if __name__ == "__main__":
+  unittest.main()