fix: infrastructure for prod-parity deployment

Added db schema migration script (scripts/migrate.js) for fresh deployments,
updated Dockerfile to include scripts directory, and fixed job-progress test
to include newly added retry fields after D3 foundation merge.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

scripts/migrate.js

@@ -0,0 +1,16 @@
+#!/usr/bin/env node
+/**
+ * Database migration script.
+ * For this SQLite project, schema creation is idempotent and happens on handler load.
+ * This script ensures the schema is initialized by importing the handler.
+ */
+
+import('../build/handler.js')
+	.then(() => {
+		console.log('✓ Database schema initialized');
+		process.exit(0);
+	})
+	.catch((err) => {
+		console.error('✗ Failed to initialize database:', err.message);
+		process.exit(1);
+	});