security: implement tickets #28-#35 + architecture decision #30

#28 - TOTP rate limiting (verifyTotp): added totpRateLimiter (10 req/30s),
  throws TOO_MANY_REQUESTS before DB hit; 16 unit tests including rate-limit
  exceeded + userId key isolation.

#29 - /api/reports/allocations role check: only ADMIN/MANAGER/CONTROLLER may
  access; returns 403 otherwise; 9 unit tests (401 unauthenticated, 403 for
  USER/VIEWER, 200 for allowed roles + xlsx format).

#31 - pgAdmin credentials moved out of docker-compose.yml into env vars;
  PGADMIN_PASSWORD is now required (:?) to prevent accidental plaintext
  exposure in committed files.

#34 - Server-side HTML sanitization for comment bodies via stripHtml():
  strips all tags + decodes safe entities before persistence; 16 unit tests
  covering passthrough, injection patterns, entity decoding.

#35 - MFA setup prompt banner (MfaPromptBanner): shown to ADMIN/MANAGER users
  without TOTP enabled; user-scoped localStorage snooze (7 days); links to
  /account/security; accessibility role=alert; 7 structural unit tests.

#33 - Auth anomaly alerting cron (/api/cron/auth-anomaly-check): detects
  HIGH_GLOBAL_FAILURE_RATE and CONCENTRATED_FAILURES in 30-minute window;
  CRITICAL notification to ADMINs; fail-closed via verifyCronSecret;
  10 unit tests.

#32 - MFA enforcement policy: added requireMfaForRoles field to SystemSettings
  schema + Prisma migration; auth.ts blocks login with MFA_REQUIRED_SETUP
  signal if role is enforced but TOTP not set up; signin page redirects to
  /account/security?mfa_required=1; settings schema + view model updated;
  11 unit tests.

#30 - API keys architecture decision documented in LEARNINGS.md; no code
  written — product decision required before implementation.

Co-Authored-By: claude-flow <ruv@ruv.net>

packages/db/prisma/schema.prisma

@@ -1572,6 +1572,9 @@ model SystemSettings {
   sessionIdleTimeout      Int?     @default(1800)     // Idle timeout in seconds (30min)
   // Concurrent session limit (kick-oldest strategy)
   maxConcurrentSessions   Int?     @default(3)
+  // MFA enforcement: roles that are required to have TOTP enabled (JSON array of SystemRole strings)
+  // e.g. ["ADMIN"] or ["ADMIN","MANAGER"]. Null = no enforcement.
+  requireMfaForRoles      Json?    @db.JsonB
   updatedAt               DateTime @updatedAt
 
   @@map("system_settings")