v1.4.0: web configurator

New: the configurator. Enter a username, pick effects and options, and see them rendered live on that profile's public data with the same code the Action runs. Then set it up with one click (GitHub opens with the workflow prefilled), the one-line installer, or the YAML.

• Generated workflows now run right after the file is added, and queue instead of racing.
• install.sh supports README_POSITION and writes the same workflow as the configurator.
• Internals: the CLI's logic moved into shared modules; Action output is byte-identical to v1.3.1.

Nothing to do if you use @v1.