Anonymize sensitive information and add SSH setup documentation

Documentation:
- Add comprehensive SSH key setup guide in docs/SSH-SETUP.md
- Add SSH configuration sections to README.md and QUICKSTART.md
- Replace specific provider examples with generic alternatives
- Remove Hetzner/BorgBase specific instructions for broader applicability

Anonymization:
- Remove company/project specific names (Agence66 → generic)
- Generalize service names (/srv/app → /srv/*)
- Remove detailed application lists (/opt/nextcloud, etc. → /opt/*)
- Replace specific usernames and hostnames with placeholders
- Change repository label from 'serveur' to 'production'

Files updated:
- README.md: Add SSH setup, anonymize content
- QUICKSTART.md: Add SSH configuration steps
- CHANGELOG.md: Generalize paths list
- config.yaml: Generic title and label
- install.sh: Remove branding
- scripts/healthcheck.sh: Remove branding
- docs/SSH-SETUP.md: New comprehensive SSH guide

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

QUICKSTART.md

@@ -45,13 +45,34 @@ NTFY_URL=https://ntfy.sh/votre-topic
 NTFY_USER=username:password
 ```
 
+## Configuration SSH (repository distant)
+
+Si votre repository est distant, configurez d'abord les clés SSH :
+
+```bash
+# Générer une clé SSH
+sudo ssh-keygen -t ed25519 -C "borgmatic-backup"
+# Appuyez sur Entrée 3 fois (emplacement par défaut, pas de passphrase)
+
+# Copier la clé sur le serveur
+sudo ssh-copy-id -p PORT user@backup-server.com
+
+# Tester (ne doit pas demander de mot de passe)
+sudo ssh -p PORT user@backup-server.com
+
+# Si ssh-copy-id ne fonctionne pas, méthode manuelle :
+# 1. Afficher la clé : sudo cat /root/.ssh/id_ed25519.pub
+# 2. Se connecter : ssh -p PORT user@backup-server.com
+# 3. Ajouter : echo "VOTRE_CLE" >> ~/.ssh/authorized_keys
+```
+
 ## Initialiser le repository (si nouveau)
 
 ```bash
 # Repository local
 borg init --encryption=repokey-blake2 /path/to/repo
 
-# Repository distant
+# Repository distant (SSH doit être configuré d'abord)
 borg init --encryption=repokey-blake2 ssh://user@server/path/to/repo
 
 # IMPORTANT: Sauvegarder la clé !