Reorganize repo: one folder per application under apps/.

Move docker/ and configs/ into apps/<name>/ with config/ subfolders.
Proxmox split into hosts/pve and hosts/dell-proxmox. Nginx under
infrastructure/. Update sync script, RESTORE.md, and per-app READMEs.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/radarr/README.md

@@ -0,0 +1,10 @@
+# Radarr
+
+Config-only (draait op Proxmox LXC).
+
+| | |
+|---|---|
+| **Git** | `config/config.xml` |
+| **NAS** | `/volume1/docker/Configs/Radarr` |
+
+Sync: `sh scripts/sync-from-nas.sh`