feat: Mini-Cloud Plattform - komplette Implementierung Phase 0-8

Selbstgehostete Web-Cloud mit Dateiverwaltung, Kalender, Kontakte,
Email-Webclient, Office-Viewer und Passwort-Manager.

Backend (Flask/Python):
- JWT-Auth mit Access/Refresh Tokens, Benutzerverwaltung
- Dateien: Upload/Download, Ordner, Berechtigungen, Share-Links
- Kalender: CRUD, Teilen, iCal-Export, CalDAV well-known URLs
- Kontakte: Adressbuecher, vCard-Export, Teilen
- Email: IMAP/SMTP-Proxy, Multi-Account
- Office-Viewer: DOCX/XLSX/PPTX/PDF Vorschau
- Passwort-Manager: AES-256-GCM clientseitig, KeePass-Import
- Sync-API fuer Desktop/Mobile-Clients
- SQLite mit WAL-Modus

Frontend (Vue 3 + PrimeVue):
- Datei-Explorer mit Breadcrumbs und Share-Dialogen
- Monatskalender mit Event-Verwaltung
- Kontaktliste mit Adressbuch-Sidebar
- Email-Client mit 3-Spalten-Layout
- Passwort-Manager mit TOTP und Passwort-Generator
- Admin-Panel, Settings, oeffentliche Share-Seite

Docker: Multi-Stage Build, Bind Mounts (keine Volumes)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/models/email_account.py

@@ -0,0 +1,41 @@
+from datetime import datetime, timezone
+
+from app.extensions import db
+
+
+class EmailAccount(db.Model):
+    __tablename__ = 'email_accounts'
+
+    id = db.Column(db.Integer, primary_key=True)
+    user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False, index=True)
+    display_name = db.Column(db.String(100), nullable=False)  # e.g. "Arbeit", "Privat"
+    email_address = db.Column(db.String(255), nullable=False)
+    imap_host = db.Column(db.String(255), nullable=False)
+    imap_port = db.Column(db.Integer, default=993)
+    imap_ssl = db.Column(db.Boolean, default=True)
+    smtp_host = db.Column(db.String(255), nullable=False)
+    smtp_port = db.Column(db.Integer, default=587)
+    smtp_ssl = db.Column(db.Boolean, default=True)  # STARTTLS
+    username = db.Column(db.String(255), nullable=False)
+    password_encrypted = db.Column(db.LargeBinary, nullable=False)
+    is_default = db.Column(db.Boolean, default=False)
+    sort_order = db.Column(db.Integer, default=0)
+    created_at = db.Column(db.DateTime, default=lambda: datetime.now(timezone.utc))
+    updated_at = db.Column(db.DateTime, default=lambda: datetime.now(timezone.utc),
+                           onupdate=lambda: datetime.now(timezone.utc))
+
+    def to_dict(self):
+        return {
+            'id': self.id,
+            'display_name': self.display_name,
+            'email_address': self.email_address,
+            'imap_host': self.imap_host,
+            'imap_port': self.imap_port,
+            'imap_ssl': self.imap_ssl,
+            'smtp_host': self.smtp_host,
+            'smtp_port': self.smtp_port,
+            'smtp_ssl': self.smtp_ssl,
+            'username': self.username,
+            'is_default': self.is_default,
+            'sort_order': self.sort_order,
+        }