feat(db): add core Drizzle schema tables (hardware, games, gameVersions)

- Create lib/db/schema/ directory with barrel export index.ts
- Add hardware table with device_type enum (handled/console)
- Add games table with Steam metadata, sync fields, and JSON genres
- Add game_versions table with composite unique (gameId, buildId) and cascade delete

Refs: Chunk 2 of database schema implementation

lib/db/schema/games.ts

@@ -0,0 +1,27 @@
+import {
+  boolean,
+  integer,
+  jsonb,
+  pgTable,
+  text,
+  timestamp,
+} from "drizzle-orm/pg-core"
+
+export const games = pgTable("games", {
+  id: text("id")
+    .primaryKey()
+    .$defaultFn(() => crypto.randomUUID()),
+  steamAppId: integer("steam_app_id").unique().notNull(),
+  title: text("title").notNull(),
+  description: text("description"),
+  publisher: text("publisher"),
+  developer: text("developer"),
+  genres: jsonb("genres").$type<string[]>(),
+  headerImage: text("header_image"),
+  capsuleImage: text("capsule_image"),
+  storeUrl: text("store_url"),
+  lastSync: timestamp("last_sync"),
+  syncStatus: text("sync_status").default("pending"),
+  createdAt: timestamp("created_at").defaultNow().notNull(),
+  updatedAt: timestamp("updated_at").defaultNow().notNull(),
+})