feat: redesign match play and add broadcast tooling

scripts/migrations/0006-predictions.sql

@@ -0,0 +1,18 @@
+-- Spectator predictions and tournament pick'ems.
+CREATE TABLE IF NOT EXISTS prediction (
+	id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+	user_id text NOT NULL,
+	match_id uuid REFERENCES match(id) ON DELETE CASCADE,
+	tournament_match_id uuid REFERENCES tournament_match(id) ON DELETE CASCADE,
+	winner_team_id uuid NOT NULL REFERENCES team(id) ON DELETE CASCADE,
+	winner_score integer,
+	loser_score integer,
+	points integer,
+	created_at timestamptz NOT NULL DEFAULT now(),
+	updated_at timestamptz NOT NULL DEFAULT now(),
+	CONSTRAINT prediction_one_subject CHECK ((match_id IS NULL) <> (tournament_match_id IS NULL))
+);
+CREATE UNIQUE INDEX IF NOT EXISTS idx_prediction_user_match ON prediction (user_id, match_id);
+CREATE UNIQUE INDEX IF NOT EXISTS idx_prediction_user_tmatch ON prediction (user_id, tournament_match_id);
+CREATE INDEX IF NOT EXISTS idx_prediction_match ON prediction (match_id);
+CREATE INDEX IF NOT EXISTS idx_prediction_tmatch ON prediction (tournament_match_id);