[wrangler] D1 SQL splitter does not treat bracket-quoted identifiers as quoted

### Which Cloudflare product(s) does this pertain to?

Wrangler core, D1

### What versions are you using?

`main` (reproduced at 898dc6e)

### Describe the Bug

`splitSqlIntoStatements()` in `packages/wrangler/src/d1/splitter.ts` scans for quotes so that SQL syntax inside them is not interpreted. It handles `'`, `"` and backticks, but not SQLite's bracket-quoted identifiers (`[name]`).

As a result a trigger body that references such an identifier is split apart. Given:

```sql
CREATE TRIGGER t AFTER INSERT ON items
BEGIN
UPDATE x SET [end] = 1;
UPDATE y SET z = 2;
END;
SELECT 1;
```

`splitSqlQuery()` returns four fragments instead of two:

```
CREATE TRIGGER t AFTER INSERT ON items\nBEGIN\n UPDATE x SET [end] = 1
UPDATE y SET z = 2
END
SELECT 1
```

Each fragment is then sent to D1 separately, so `wrangler d1 execute --file` and `wrangler d1 migrations apply` fail or apply a migration partially.

Notably `normalizeSqlLineEndings()`, in the same file, *does* treat `[` … `]` as a quote pair, so the two scanners disagree about the same syntax.

### Please provide a link to a minimal reproduction

The snippet above reproduces directly through `splitSqlQuery()`; no account or network access is needed.

### Additional context

Found while working on #15226, which fixes a different splitter issue (compound statement markers that are not padded with whitespace). This one is pre-existing and independent — it reproduces identically before and after that change — and needs a fix in the scanner rather than in the marker regexes, so it is filed separately. Happy to send a PR.

Start in packages/wrangler/src/d1/splitter.ts, reading splitSqlIntoStatements() alongside normalizeSqlLineEndings() to compare their quote handling. Reproduce the supplied trigger through splitSqlQuery() without network access, then add coverage showing bracket-quoted identifiers remain within one statement and the example yields two fragments.

Written by the indexing model from the issue text.