chore(db): add query indexes migration and update project config

- Add database migration for missing query indexes on frequently filtered columns
- Update Prisma schema
- Update .env.example, eslint config, and dependency-cruiser config

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

.env.example

@@ -139,6 +139,16 @@ SENTRY_AUTH_TOKEN=
 SENTRY_ORG=
 SENTRY_PROJECT=
 
+# -----------------------------------------------------------------------------
+# KYC Field Encryption (REQUIRED in production)
+#
+# AES-256-GCM key for encrypting sensitive KYC data at rest.
+# Must be exactly 64 hex characters (32 bytes).
+#   openssl rand -hex 32
+# -----------------------------------------------------------------------------
+KYC_ENCRYPTION_KEY=<generate with: openssl rand -hex 32>
+KYC_ENCRYPTION_KEY_VERSION=1
+
 # -----------------------------------------------------------------------------
 # Logging
 # -----------------------------------------------------------------------------