`append()` doesn't work in neon-serverless driver

[toshimo]

Description

When using waddler/neon-serverless, SQL queries built with append() fail with a syntax error. The toSQL() method returns the correct SQL, but the query sent to the database only contains the initial SQL fragment.

Reproduction

import { waddler } from "waddler/neon-serverless";

const sql = waddler({ connection: "postgresql://...@...-pooler.neon.tech/..." });

// Works: direct template literal
await sql`WITH cte AS (SELECT 1 as num) SELECT * FROM cte`;  // ✅ OK

// Fails: using append()
const query = sql`WITH`;
query.append(sql` cte AS (SELECT 1 as num)`);
query.append(sql` SELECT * FROM cte`);

console.log(query.toSQL());
// → { sql: "WITH cte AS (SELECT 1 as num) SELECT * FROM cte", params: [] }  ✅ Correct

console.log((query as any).queryConfig.text);
// → "WITH"  ❌ Still the initial value!

await query;
// Error: syntax error at end of input (position: 5)

Root Cause

In NeonServerlessSQLTemplate, queryConfig.text is set once in the constructor and never updated after append() calls:

// Constructor - sets queryConfig.text once
constructor(sqlWrapper, client, dialect, configOptions, options) {
  // ...
  const query = this.sqlWrapper.getQuery(this.dialect).sql;
  this.queryConfig = {
    rowMode: "array",
    text: query,  // ← Fixed at construction time
    types: pgTypeConfig,
  };
}

// execute() - uses stale queryConfig
async execute() {
  const { sql: query, params } = this.sqlWrapper.getQuery(this.dialect);
  // query is correct here, but queryConfig.text is stale
  const queryResult = await this.client.query(this.queryConfig, params);
  // ↑ Sends the old SQL text
}

Proposed Fix

The fix is minimal - just update queryConfig.text and rawQueryConfig.text in execute() before sending the query:

async execute() {
  const { sql: query, params } = this.sqlWrapper.getQuery(this.dialect);
  this.queryConfig.text = query;      // ← Add this
  this.rawQueryConfig.text = query;   // ← Add this
  // ... rest unchanged
}

Happy to open a PR if this approach looks good.

Environment

• waddler version: 0.1.1
• Driver: waddler/neon-serverless
• Database: Neon PostgreSQL (pooler connection)