Add AL docs for PEPPOL

[Groenbech96]

Summary

• Bootstrap documentation for PEPPOL
• Generated by /al-docs init

Test plan

• Verify docs render correctly on GitHub
• Verify all claims trace to actual source code

🤖 Generated with Claude Code

[github-actions]

Could not find a linked ADO work item. Please link one by using the pattern 'AB#' followed by the relevant work item number. You may use the 'Fixes' keyword to automatically resolve the work item when the pull request is merged. E.g. 'Fixes AB#1234'

[Groenbech96]

This fails

Every export follows the same sequence regardless of document type:

Unable to render rich display

Parse error on line 13:
...cord Export Buffer."File Content"]
-----------------------^
Expecting 'SQE', 'DOUBLECIRCLEEND', 'PE', '-)', 'STADIUMEND', 'SUBROUTINEEND', 'PIPE', 'CYLINDEREND', 'DIAMOND_STOP', 'TAGEND', 'TRAPEND', 'INVTRAPEND', 'UNICODE_TEXT', 'TEXT', 'TAGSTART', got 'STR'

For more information, see https://docs.github.com/get-started/writing-on-github/working-with-advanced-formatting/creating-diagrams#creating-mermaid-diagrams