Session log: GuruRMM MSI build fix + DESIGN.md + BirthBiologic onboarding

- Fixed MSI build on Pluto (missing WixToolset.Util.wixext in install.rs)
- Created docs/DESIGN.md in gururmm repo (per-component design guide)
- Saved BirthBiologic GuruRMM site credentials to vault
- Added birth-biologic and mvan-inc client session logs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/skills/remediation-tool/references/gotchas.md

@@ -120,6 +120,7 @@ If token request or API call returns AADSTS650052 referencing `WindowsDefenderAT
 | Cascades Tucson | 207fa277-e9d8-4eb7-ada1-1064d2221498 | old app only | — | — | — | — | old app only | old app only | — | IdentityRiskyUser scope still not consented as of 2026-04-16 |
 | Grabblaw | 032b383e-96e4-491b-880d-3fd3295672c3 | YES (2026-04-20) | — | YES (2026-04-20) | YES (2026-04-20) | — | ASSIGNED (2026-04-20) | ASSIGNED (2026-04-20) | ASSIGNED (2026-04-20) | Fully onboarded |
 | martylryan.com | (resolve via script) | YES (2026-04-20) | — | YES (old app) | YES (2026-04-20) | — | ASSIGNED (2026-04-20) | ASSIGNED (2026-04-20) | ASSIGNED (2026-04-20) | Fully onboarded |
+| mvaninc.com | 5affaf1e-de89-416b-a655-1b2cf615d5b1 | YES (2026-04-21) | — | YES (2026-04-21) | YES (2026-04-21) | — | — | — | — | Fully onboarded. Incident 2026-04-21: sysadmin GA account unauthorized sign-in from OKC via device PRT (MITCH-LAPTOP/JUNE). Remediated: pw reset, sessions revoked. CA policy (MFA all users) still pending — Mike to create. |
 
 **Migration note:** Valleywide, Dataforth, and Cascades still use the old deprecated app. Next visit: consent Security Investigator + assign Exchange Administrator role to new SP, then retire old app consent.