docs: add MSSP guide for deploying Viberails via EDR Payloads

[maximelb]

Summary

• Adds a new tutorial: Viberails Deployment (MSSP) under 2-sensors-deployment/tutorials/.
• Walks MSSPs through using existing LimaCharlie coverage (Payloads, D&R rules, Payload Manager / Git-Sync) to roll Viberails out to developer workstations across every customer org.
• Provides ready-to-use D&R rule templates for Windows, macOS, and Linux, plus the user-context caveat (endpoint agent runs as SYSTEM/root, hooks need to land in the developer's profile).
• Adds the page to the mkdocs nav under Sensors → Tutorials.

Why a draft

This is a first cut that needs review on:

• The exact CLI/D&R commands used for dropping privileges to the active console user (Windows uses a one-shot scheduled task with /RU INTERACTIVE; macOS uses launchctl asuser + sudo -u; Linux uses who + sudo -u). These are conventional patterns but may need adjustment based on agent capabilities and how MSSPs actually operate in practice.
• Whether one-shared-team vs one-team-per-customer should be opinionated rather than left as a customer choice.
• Whether the Viberails README links (e.g. troubleshooting, configuration) should point at docs.viberails.io once that exists.

Test plan

• npx markdownlint-cli2 passes locally (verified — 0 errors).
• mkdocs build renders without warnings.
• Reviewers walk through the D&R rules on a sandbox sensor (Windows + macOS + Linux) and confirm Viberails ends up installed under the right user account.
• Internal links resolve (payloads.md, payload-manager.md, git-sync.md, sensor-tags.md, mssp-msp-mdr.md, designing-access.md).

🤖 Generated with Claude Code

[github-actions]

Broken Links Detected

The link checker found some issues:

* [ERROR] <file:///home/runner/work/documentation/documentation/site/8-reference/story-tags/asset-tags.md> | Cannot find file: File not found. Check if file exists and path is correct

Please fix these broken links before merging.

Full results

See the uploaded artifact for complete link check results.