Add enterprise admin alert escalation guard

[GHX5T-SOL]

/claim #19

PR URL: #353
Commit: f5eb961

Summary:

• add a self-contained enterprise admin notification escalation guard for Enterprise Tooling
• validate synthetic compliance, integration, dashboard, and webhook alerts before they are muted, digested, throttled, or routed to inactive owners
• enforce high-severity digest/mute bypass, owner fallback, webhook-health fallback, quiet-hours override, duplicate-suppression safety, dashboard badges, webhook-ready event summaries, and deterministic audit packets

Safety:

• synthetic fixtures only in enterprise-admin-alert-escalation-guard/sample-data.js
• no live email, SMS, Slack, webhook delivery, external providers, private users, credentials, or real institutional alert data

Proof/demo:

• enterprise-admin-alert-escalation-guard/reports/demo.mp4

Validation:

• npm run check
• npm test (7 tests)
• npm run demo
• ffprobe -v error -select_streams v:0 -show_entries stream=codec_name,width,height,duration,avg_frame_rate -show_entries format=size,duration -of default=noprint_wrappers=1 enterprise-admin-alert-escalation-guard/reports/demo.mp4 -> H.264, 1280x720, 4 seconds, 25 fps, 58,187 bytes
• git diff --check
• git diff --cached --check
• gitleaks detect --source /home/kali/money/worktrees/scibase-ai --no-git --redact --exit-code 1 -> no leaks found

No secrets, tokens, private dashboard data, payout details, or unrelated changes are included.