feat(security+ai): security hardening + FluxAI conversation analytics

Security (critical):
- SESSION_SECRET fail-fast: refuse to boot without a 32+ char secret
  (src/lib/session.ts, src/app/actions/clientAuth.ts)
- Rate limit with pluggable backend: in-memory by default, auto-promotes
  to Upstash Redis when REDIS_URL is set (src/lib/rateLimit.ts)
- CSRF (double-submit HMAC) + Zod validation on /api/consultation;
  new /api/csrf endpoint mints tokens (src/lib/csrf.ts)
- escapeHtml + safeMailto helpers; consultation email template now
  fully escapes user-controlled fields (src/lib/escapeHtml.ts)
- Magic-byte validation for /api/public-upload — rejects HTML/JS
  payloads renamed to .png/.mp4 (src/lib/fileType.ts)
- Nginx: CSP, X-Frame-Options, X-Content-Type-Options, Referrer-Policy,
  Permissions-Policy + 5r/m upload zone for /api/public-upload and
  /api/assets (nginx/conf.d/flux.conf)

Quality:
- Delete GlobalOperations_old.tsx dead code (310 LOC)
- NavBar: replace 2s session polling with CustomEvent("flux:session-
  changed") + visibilitychange listener (no more interval leaks)
- Type-safe CMS shapes via src/types/cms.ts (replaces any[] in
  ApplicationsDashboard + GlobalOperations)
- /api/health now pings Postgres; docker-compose healthcheck added
- Structured JSON logger (src/lib/logger.ts) — drop-in replacement
  for console.error across API routes
- Prisma indices on isActive/category/nodeType filters

FluxAI persistence + analytics:
- New models AiConversation + AiEvent with funnel stage detection
  (DISCOVERY -> QUALIFY -> RECOMMEND -> HANDOFF) and OperationsSignal
  back-ref so converted chats link to their consultation ticket
- /api/chat persists every user msg, ai msg, tool call, tool result;
  IP is sha256-hashed with SESSION_SECRET salt; promptCacheKey wired
  for when @ai-sdk/openai lands the feature
- New HQ dashboard at /hq-command/dashboard/conversations: 4 KPIs
  (total, conversion rate, avg messages, avg tools), funnel + industry
  breakdowns, last-50 table, per-id transcript with tool timeline
- SilentObserver sends sessionId/locale/pageUrl in transport body so
  the route can stitch messages into the same conversation
- src/lib/aiSessionId.ts: localStorage UUID with sessionStorage +
  in-memory fallbacks for privacy mode
- Golden tests via node --test (13 cases, no new deps);
  npm run test:ai

Migration:
- prisma/migrations/20260526180000_add_indexes_and_ai_telemetry —
  additive only, IF NOT EXISTS guards, safe for migrate deploy

env template hardened: SESSION_SECRET documented as required + how
to generate; REDIS_URL/REDIS_TOKEN documented as opt-in for multi-
instance deploys.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/actions/clientAuth.ts

@@ -5,7 +5,13 @@ import bcrypt from "bcryptjs";
 import { cookies } from "next/headers";
 import { SignJWT, jwtVerify } from "jose";
 
-const getSecretKey = () => new TextEncoder().encode(process.env.SESSION_SECRET || "flux-super-secret-key-2026");
+const getSecretKey = () => {
+  const s = process.env.SESSION_SECRET;
+  if (!s || s.length < 32) {
+    throw new Error("SESSION_SECRET environment variable is required (min 32 chars).");
+  }
+  return new TextEncoder().encode(s);
+};
 
 export async function registerClientRequest(formData: FormData) {
   const fullName = formData.get("fullName") as string;