feat: add quoteStrings option to force quoting strings in encoder (#102)

[heysebitas]

Summary

This PR adds a new quoteStrings option to the encoder, allowing users to force wrapping all string values in quotes during formatting.

Context

Some users need strict quoting behavior for string output — especially when working with data pipelines, structured logs, or formats that must always explicitly represent strings.

Issue reference: #102

What’s included

• Adds a new quoteStrings?: boolean option to the encoder config.
• When enabled, all string values are forced to be quoted, regardless of content.
• Updates TypeScript types and propagates the option through the encoding pipeline.
• Adds tests to cover both default and quoteStrings: true scenarios.

Example

encode({ value: "hello" }, { quoteStrings: true })
// → value: "hello"