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/20260411100000_add_pii_encryption_hash_columns/migration.sql

@@ -0,0 +1,34 @@
+-- =============================================================================
+-- Migration: Add hash columns for field-level PII encryption
+--
+-- This migration adds deterministic HMAC-SHA256 hash columns alongside
+-- encrypted PII fields to support indexed lookups (WHERE / UNIQUE).
+--
+-- The original email/phone columns will hold encrypted ciphertext after
+-- the backfill script runs. Uniqueness shifts to the hash columns.
+-- =============================================================================
+
+-- ---------- User ----------
+
+-- Drop existing unique constraints on plaintext columns
+-- These will be replaced by unique constraints on hash columns
+ALTER TABLE "User" DROP CONSTRAINT IF EXISTS "User_email_key";
+ALTER TABLE "User" DROP CONSTRAINT IF EXISTS "User_phone_key";
+
+-- Add hash columns
+ALTER TABLE "User" ADD COLUMN "emailHash" TEXT;
+ALTER TABLE "User" ADD COLUMN "phoneHash" TEXT;
+
+-- Unique indexes on hash columns (replace the old plaintext unique constraints)
+CREATE UNIQUE INDEX "User_emailHash_key" ON "User"("emailHash");
+CREATE UNIQUE INDEX "User_phoneHash_key" ON "User"("phoneHash");
+
+-- ---------- Lead ----------
+
+-- Add hash columns
+ALTER TABLE "Lead" ADD COLUMN "phoneHash" TEXT;
+ALTER TABLE "Lead" ADD COLUMN "emailHash" TEXT;
+
+-- Non-unique indexes for Lead hash columns (leads can share phone/email)
+CREATE INDEX "Lead_phoneHash_idx" ON "Lead"("phoneHash");
+CREATE INDEX "Lead_emailHash_idx" ON "Lead"("emailHash");