feat: add email notification system (Brevo SMTP + N8N daily digest)

- Add core notification service: types, email-service (nodemailer/Brevo SMTP), notification-service (digest builder, preference CRUD, HTML renderer)
- Add API routes: POST /api/notifications/digest (N8N cron, Bearer auth), GET/PUT /api/notifications/preferences (session auth)
- Add NotificationPreferences UI component (Bell button + dialog with per-type toggles) in Registratura toolbar
- Add 7 Brevo SMTP env vars to docker-compose.yml
- Update CLAUDE.md, ROADMAP.md, DATA-MODEL.md, SYSTEM-ARCHITECTURE.md, CONFIGURATION.md, DOCKER-DEPLOYMENT.md

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package-lock.json

@@ -21,6 +21,7 @@
         "next": "16.1.6",
         "next-auth": "^4.24.13",
         "next-themes": "^0.4.6",
+        "nodemailer": "^7.0.13",
         "proj4": "^2.20.3",
         "qrcode": "^1.5.4",
         "radix-ui": "^1.4.3",
@@ -36,6 +37,7 @@
         "@tailwindcss/postcss": "^4",
         "@types/jszip": "^3.4.0",
         "@types/node": "^20",
+        "@types/nodemailer": "^7.0.11",
         "@types/proj4": "^2.5.6",
         "@types/qrcode": "^1.5.6",
         "@types/react": "^19",
@@ -4034,6 +4036,16 @@
         "undici-types": "~6.21.0"
       }
     },
+    "node_modules/@types/nodemailer": {
+      "version": "7.0.11",
+      "resolved": "https://registry.npmjs.org/@types/nodemailer/-/nodemailer-7.0.11.tgz",
+      "integrity": "sha512-E+U4RzR2dKrx+u3N4DlsmLaDC6mMZOM/TPROxA0UAPiTgI0y4CEFBmZE+coGWTjakDriRsXG368lNk1u9Q0a2g==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/node": "*"
+      }
+    },
     "node_modules/@types/pako": {
       "version": "2.0.4",
       "resolved": "https://registry.npmjs.org/@types/pako/-/pako-2.0.4.tgz",
@@ -9943,6 +9955,16 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/nodemailer": {
+      "version": "7.0.13",
+      "resolved": "https://registry.npmjs.org/nodemailer/-/nodemailer-7.0.13.tgz",
+      "integrity": "sha512-PNDFSJdP+KFgdsG3ZzMXCgquO7I6McjY2vlqILjtJd0hy8wEvtugS9xKRF2NWlPNGxvLCXlTNIae4serI7dinw==",
+      "license": "MIT-0",
+      "peer": true,
+      "engines": {
+        "node": ">=6.0.0"
+      }
+    },
     "node_modules/npm-run-path": {
       "version": "6.0.0",
       "resolved": "https://registry.npmjs.org/npm-run-path/-/npm-run-path-6.0.0.tgz",