feat: add MFA/TOTP auth, PII encryption, agents/leads/inquiries modules, and comprehensive tests

- Add TOTP-based MFA with setup, verify, disable, backup codes, and challenge flow
- Add PII field encryption middleware with AES-256-GCM and deterministic search hashes
- Add agents, inquiries, and leads domain modules with entities, events, value objects
- Add web dashboard pages for inquiries and leads with detail dialogs
- Add 30+ component tests (valuation, charts, listings, search, providers, UI)
- Add Prisma migrations for encryption hash columns and MFA TOTP support
- Fix all ESLint errors (unused imports, duplicate imports, lint auto-fixes)
- Update dependencies and lock file
- Clean up obsolete exploration/QA docs, add audit documentation

Co-Authored-By: Paperclip <noreply@paperclip.ing>

prisma/migrations/20260411200000_add_mfa_totp_support/migration.sql

@@ -0,0 +1,29 @@
+-- AddMfaTotpSupport
+-- Add TOTP-based MFA fields to User model and MfaChallenge table
+
+-- Add MFA columns to User
+ALTER TABLE "User" ADD COLUMN "totpSecret" TEXT;
+ALTER TABLE "User" ADD COLUMN "totpEnabled" BOOLEAN NOT NULL DEFAULT false;
+ALTER TABLE "User" ADD COLUMN "totpBackupCodes" TEXT[] DEFAULT ARRAY[]::TEXT[];
+ALTER TABLE "User" ADD COLUMN "totpEnabledAt" TIMESTAMP(3);
+
+-- Create MfaChallenge table for login verification flow
+CREATE TABLE "MfaChallenge" (
+    "id" TEXT NOT NULL,
+    "userId" TEXT NOT NULL,
+    "type" TEXT NOT NULL,
+    "attemptCount" INTEGER NOT NULL DEFAULT 0,
+    "maxAttempts" INTEGER NOT NULL DEFAULT 5,
+    "isVerified" BOOLEAN NOT NULL DEFAULT false,
+    "expiresAt" TIMESTAMP(3) NOT NULL,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "MfaChallenge_pkey" PRIMARY KEY ("id")
+);
+
+-- Indexes
+CREATE INDEX "MfaChallenge_userId_expiresAt_idx" ON "MfaChallenge"("userId", "expiresAt");
+CREATE INDEX "MfaChallenge_expiresAt_idx" ON "MfaChallenge"("expiresAt");
+
+-- Foreign key
+ALTER TABLE "MfaChallenge" ADD CONSTRAINT "MfaChallenge_userId_fkey" FOREIGN KEY ("userId") REFERENCES "User"("id") ON DELETE CASCADE ON UPDATE CASCADE;