docs: sync skills pack to n8n-skills v1.28.0 (folder management) (czlonkowski#976)

* docs: sync skills pack to n8n-skills v1.28.0 (folder management)

The bundled pack predates the 2.68.0 folder feature. Synced from
n8n-skills v1.28.0: n8n_manage_folders (six actions, list counts,
recursive totals, delete/archive semantics), the moveToFolder diff
operation, and parentFolderId on workflow create - including the
write-only placement and delete-archives-workflows behaviors.

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* docs: sync Copilot review polish from n8n-skills v1.28.1

Explicit folderId placeholder in the moveToFolder verification example;
router delete note clarifies workflows move to the project root and are
archived, not removed.

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

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Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: czlonkowski