feat(Properties): add Properties / JSON BoxSource

[XiaoXiaoSN]

Box Source: Properties / JSON (Convert)

Adds the Properties / JSON box source to Magic Box. It is disabled by default.

Details:

• Category (Kind): Convert
• Tag: #
• Default Input: server.host=localhost server.port=8080 ::properties

Options:

• ::properties, ::propertiesjson

Description:

Convert a Java .properties file to JSON, or a flat JSON object to .properties.

Usage Examples:

• Input:

server.host=localhost
server.port=8080
::properties

• Output Box (Properties → JSON):

{
  "server.host": "localhost",
  "server.port": "8080"
}

[XiaoXiaoSN]

Linting/testing failed on this branch.

Error details:

Please fix the linting and testing issues and ensure 'bun run lint' and 'bun test run' pass.

[XiaoXiaoSN]

This PR is ready to merge!