Scope live chat to the current match and save match history

src/lib/server/db/schema.sql

@@ -40,6 +40,15 @@ CREATE INDEX IF NOT EXISTS idx_leaderboard_server ON leaderboard_matches(server,
 CREATE INDEX IF NOT EXISTS idx_leaderboard_started ON leaderboard_matches(started_at DESC, id DESC);
 CREATE INDEX IF NOT EXISTS idx_leaderboard_map ON leaderboard_matches(game, map_key);
 
+-- Chat follows match retention and survives deletion of the live server.
+CREATE TABLE IF NOT EXISTS match_chat (
+    match_id INTEGER NOT NULL REFERENCES leaderboard_matches(id) ON DELETE CASCADE,
+    message_key TEXT NOT NULL,
+    occurrence INTEGER NOT NULL,
+    entry TEXT NOT NULL,
+    PRIMARY KEY (match_id, message_key, occurrence)
+);
+
 CREATE TABLE IF NOT EXISTS leaderboard_players (
     game TEXT NOT NULL,
     guid TEXT NOT NULL,