Add cli option to exclude presenter notes from HTML output

Currently, Marp cli includes presenter notes in the generated HTML output.

While these notes are hidden in the presentation view and only visible in presenter mode (via the 'P' key), they remain in the HTML source code.

Use Case:

When sharing HTML presentations with clients or external parties, presenters may want to completely exclude their internal notes from the deliverable file, rather than just hiding them visually.

Proposed Solution:

Add a cli flag to exclude presenter notes from the output.

Example:

marp presentation.md -o output.html --skip-notes

Current Workarounds:

• Manually removing notes from source markdown
• Post-processing HTML with scripts
• Maintaining separate versions of presentations

Benefits:

• Cleaner deliverables for client-facing presentations
• No risk of exposing internal notes
• Simpler workflow for users who share presentations

Start at the Marp CLI option handling and the HTML output path that includes presenter notes. Add the documented --skip-notes behavior from the example, then verify that generated HTML omits presenter notes while normal output remains unchanged.