feat(db): generate canonical schema contract from sqlite migrations

scripts/dev/generate-schema-contract.ts

@@ -0,0 +1,6 @@
+import { writeSchemaContractFile } from '../../src/server/db/schemaContract.js';
+
+const contract = writeSchemaContractFile();
+const tableCount = Object.keys(contract.tables).length;
+
+console.log(`[schema:contract] wrote ${tableCount} tables`);