Description:
Draft a high-level introduction document to OCM for the new "Introduction" section.

Scope:

• Write an overview document of how OCM works using the 4 steps, Pack, Sign, Transport, Deploy
• Focus on the end-to-end process: Pack (instead of Describe) → Sign → Transport → Deploy
• Add cross-references to concepts, guides, and tutorials. Targets can be empty and just contain "Work in progress".

Definition of Done

• Introduction Document is written
• Steps (Pack → Sign → Transport → Deploy) are clearly described
• Cross-references to concepts, guides, and tutorials are included

Out of Scope

• new graphics are not part of this issue
• they will be added in a new task that needs to be created