fix(aws-lambda): build URL query string from Lattice queryStringParameters

[rokasta12]

Problem

`LatticeV2Processor.getQueryString()` (`src/adapter/aws-lambda/handler.ts:597-599`) returned the empty string unconditionally:

```ts
protected getQueryString(): string {
return ''
}
```

But `LatticeProxyEventV2.queryStringParameters` is typed `Record<string, string[] | undefined>` (handler.ts:34) and the AWS Lattice event-shape docs describe it as the canonical source for query parameters. The result: every Hono route running on a Lattice target saw `c.req.query(...)` and `c.req.queries(...)` return `undefined` / empty even when the client sent query parameters.

Fix

Build the query string from `event.queryStringParameters`, mirroring how V1 handles `multiValueQueryStringParameters` — encode keys and values via `encodeURIComponent`, support repeated values per key, skip entries without values:

```ts
protected getQueryString(event: LatticeProxyEventV2): string {
return Object.entries(event.queryStringParameters || {})
.filter(([, values]) => values && values.length > 0)
.map(([key, values]) =>
values!
.map((value) => `${encodeURIComponent(key)}=${encodeURIComponent(value)}`)
.join('&')
)
.join('&')
}
```

Test

Three new behavioral tests in `LatticeV2Processor query string handling`:

1. Single value — verifies `c.req.query('q')` returns the Lattice-supplied value.
2. Repeated values — sends `tag=red&tag=blue`, asserts `c.req.queries('tag')` returns `['red', 'blue']`.
3. Special characters — sends `John Doe` and asserts the percent-encoded URL round-trips back to the original via `c.req.query('name')`.

All three fail on `main` (return `undefined`/`[]` because `getQueryString` returns `''`); all pass with the fix.

The existing "valid Request object from version 2.0 Lattice event" test embedded the query string inside `path` (`/my/path?...`) as a workaround for the empty-string return. Per the AWS docs `path` and `queryStringParameters` are disjoint fields, so that test is now updated to use a plain path and the URL is assembled from `queryStringParameters` instead — verifying the same end-to-end shape via the canonical field.

• Add tests
• Run tests (`bun run test` — 32/32 passes)
• `bun run format:fix && bun run lint:fix`
• Add TSDoc/JSDoc — no API surface change