Auth: Verwaltung auf Magic-Link umstellen (Passwort-Login entfernt)

Backend:
- src/routers/auth.py NEU: POST /api/auth/magic-link + POST /api/auth/verify
- src/auth.py: verify_password/hash_password raus, generate_magic_token rein
- src/main.py: alter Login-Endpoint + Brute-Force-Logik raus, neuer auth-Router eingebunden
- src/config.py: ALLOWED_EMAIL + PORTAL_MAGIC_LINK_* hinzu
- src/models.py: LoginRequest raus, MagicLinkRequest etc. rein
- src/email_utils/templates.py: portal_magic_link_email Template

Frontend:
- src/static/index.html: Email-Eingabe statt Passwort, Token-Verify-Logik fuer ?token= aus URL

Datenbank-Migration (migrations/2026-05-09_portal_magic_link.py):
- portal_magic_links + portal_magic_link_attempts neu
- portal_login_attempts gedroppt
- portal_admins.email Spalte hinzu, password_hash geleert

Whitelist info@aegis-sight.de, Rate-Limit 5/15 Min, Anti-Enumeration generische Antwort.

.gitignore

@@ -3,3 +3,6 @@ __pycache__/
 .env
 logs/
 .venv/
+venv/
+data/
+*.bak-*