feat(db): Drizzle ORM schema and migrations

Schema domains: users/auth, recipes, social, meal-planning, tiers/usage, webhooks.
Includes Better Auth tables, audit_logs, site_settings, push_subscriptions,
user_model_prefs, user_nutrition_goals. Migrations 0000–0008 applied.

packages/db/drizzle.config.ts

@@ -0,0 +1,12 @@
+import { defineConfig } from "drizzle-kit";
+
+export default defineConfig({
+  schema: "./src/schema/index.ts",
+  out: "./src/migrations",
+  dialect: "postgresql",
+  dbCredentials: {
+    url: process.env["DATABASE_URL"] ?? "postgresql://epicure:epicure@localhost:5432/epicure",
+  },
+  verbose: true,
+  strict: true,
+});