Preserve explicit false/0 query values in toQueryParams (fixes getImages svg_outline_text=false)

[Copilot]

getImages requests were dropping svg_outline_text=false because query serialization filtered values using truthiness. This caused explicit boolean/number flags to be omitted from outbound Figma API URLs.

• Query serialization behavior

  • Updated toQueryParams to retain explicit false and 0 values.
  • Serialization now excludes only undefined, null, empty-string values, and empty keys.

• Endpoint-level regression coverage

  • Added a getImagesApi test asserting svg_outline_text=false is preserved in the generated URL.

• Utility-level regression coverage

  • Updated boolean serialization expectations to include disabled=false.
  • Added explicit test coverage for { svg_outline_text: false, scale: 0 }.

// before
k && v && `${k}=${encodeURIComponent(v as any)}`

// after
k && v !== undefined && v !== null && v !== '' &&
`${k}=${encodeURIComponent(v as any)}`

[didoo]

@copilot can you remove the files under the lib/ folder? these are the compiled files, and will be added (rebuilt) before the new version release

[didoo]

@copilot can you remove the files under the lib/ folder from this PR? these are the compiled files, and will be added (rebuilt) before the new version release in separate commits