fix: NetBird je samostatna aplikace (apt balicek), ne Docker sluzba

roles/netbird/tasks/main.yml:
- apt balicek 'netbird' (oficialni NetBird Linux klient)
- neni Docker, neni sluzba - je to VPN klient

roles/netbird/defaults/main.yml:
- odebrano netbird_run_as_system_service (nepotreba)
- pridana poznamka o instalaci

playbook priprav-novy-server.yml:
- hlavicka: 'NetBird (mesh VPN klient - apt balicek, NE Docker)'

group_vars/all.yml.example:
- pridana dokumentace https://docs.netbird.io/get-started/install
- komentare rikaji, ze to neni Docker sluzba

README.md:
- tabulka roli: 'apt balicek, ne Docker'
- krok 8: 'NetBird (mesh VPN klient - apt balicek)'

Postup instalace:
- Linux server: ansible role -> apt install netbird
- macOS workstation: brew install --cask netbird (v Brewfile)
- Windows: instalator z netbird.io
- Registrace: netbird up --setup-key <key> (z app.netbird.io)

group_vars/all.yml.example

@@ -19,13 +19,19 @@ deploy_ssh_public_keys:
   - "ssh-ed25519 AAAAC3Nz... hermes@mac"   # <-- nahrad svym klicem
 
 # ============================================
-# NETBIRD (mesh VPN - klient)
+# NETBIRD (mesh VPN - samostatna aplikace)
 # ============================================
+# NetBird je WireGuard-based mesh VPN klient.
+# Ne Docker sluzba - instaluje se jako apt balicek (Linux) nebo brew cask (mac).
+# Dokumentace: https://docs.netbird.io/get-started/install
+#
 # Setup key z NetBird dashboardu: https://app.netbird.io/ -> Setup Keys
 # Napr: AAAA-BBBB-CCCC-DDDD-EEEE
-# Prazdne = NetBird se nainstaluje ale nezaregistruje (setup rucne)
+#
+# Pokud je prazdne, NetBird se pouze nainstaluje - registraci provedes rucne:
+#   sudo netbird up --setup-key <tvuj-key>
+#
 netbird_setup_key: ""
-netbird_run_as_system_service: true
 netbird_management_url: "https://api.netbird.io"
 
 # ============================================