feat: configure Netdata monitoring for PostgreSQL and Restic backups

Added monitoring configurations for infrastructure services:

- **PostgreSQL monitoring** (netdata/go.d/postgres.conf):
  - Configured go.d postgres collector with netdata user credentials
  - Monitors core PostgreSQL instance at 172.18.0.5:5432
  - Tracks database performance, connections, queries, and replication

- **Restic backup monitoring** (netdata/go.d/filecheck.conf):
  - Configured go.d filecheck collector for backup repository
  - Monitors /mnt/hidrive/users/valknar/Backup directory
  - Tracks backup repository size and modification times
  - Detects backup failures via directory state changes

Infrastructure updates:
- Mounted go.d configuration directory in Netdata container
- Mounted HiDrive backup directory (read-only) for monitoring
- Persistent collector configurations across container restarts

All monitoring visible in Netdata dashboard at netdata.pivoine.art
with HTTP Basic Auth protection.

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

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

netdata/compose.yaml

@@ -13,6 +13,8 @@ services:
       - netdata_config:/etc/netdata
       - netdata_lib:/var/lib/netdata
       - netdata_cache:/var/cache/netdata
+      - ./go.d:/etc/netdata/go.d:ro
+      - /mnt/hidrive/users/valknar/Backup:/mnt/hidrive/users/valknar/Backup:ro
       - /etc/passwd:/host/etc/passwd:ro
       - /etc/group:/host/etc/group:ro
       - /etc/localtime:/etc/localtime:ro