db+game: ship_systems table + starting ship seed (new game and v4 backfill step)

lib/db/client.ts

@@ -72,6 +72,15 @@ CREATE TABLE IF NOT EXISTS crew (
   origin TEXT NOT NULL -- 'STARTING CREW' or '<planet>, <system>' for members found while exploring
 );
 
+CREATE TABLE IF NOT EXISTS ship_systems (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  save_id INTEGER NOT NULL REFERENCES saves(id),
+  type TEXT NOT NULL,
+  level INTEGER NOT NULL DEFAULT 0, -- 0 = not built yet ('built' is derived: level > 0)
+  capacity INTEGER NOT NULL DEFAULT 0,
+  UNIQUE (save_id, type)
+);
+
 CREATE TABLE IF NOT EXISTS events (
   id INTEGER PRIMARY KEY AUTOINCREMENT,
   save_id INTEGER NOT NULL REFERENCES saves(id),