v0.14.0: Per-drive backup architecture + storage path overhaul

Major refactor of backup and storage paths:

- Per-drive restic repos at <drive>/backups/primary/restic/
- Per-app DB dumps at <drive>/backups/primary/<app>/db-dumps/
- Remove global BackupDir, DBDumpDir, ResticRepo config fields
- Add SystemDataPath config (fallback for apps without HDD)
- New backup/paths.go with pure path computation helpers
- Add GetStackHDDPath to StackDataProvider interface
- Restic methods now accept repoPath as parameter
- Cross-drive backup uses new secondary path structure
- Rename storage/ to appdata/ in scripts and compose templates
- Update protected HDD paths (storage → appdata + backups)
- Simplify backup UI (remove global path displays)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/hdd-setup.sh

@@ -61,11 +61,8 @@ declare -a MEDIA_DIRS=(
     "media/books"
 )
 
-declare -a STORAGE_DIRS=(
-    "storage/immich"
-    "storage/nextcloud"
-    "storage/backups/local"
-    "storage/backups/appdata"
+declare -a BACKUP_DIRS=(
+    "backups"
 )
 
 declare -a USER_DIRS=(
@@ -170,13 +167,8 @@ FOLDER STRUCTURE CREATED:
     │   ├── series/
     │   ├── music/
     │   └── books/
-    ├── storage/
-    │   ├── immich/
-    │   ├── nextcloud/
-    │   └── backups/
-    │       ├── local/
-    │       └── appdata/
-    └── appdata/
+    ├── appdata/           (app data — created per-app on deploy)
+    └── backups/           (managed by felhom-controller)
 
 SAFETY:
     - Drives with existing data require typing "YES" to format
@@ -853,10 +845,10 @@ create_folder_structure() {
     for dir in "${MEDIA_DIRS[@]}"; do
         echo "  ├── $dir/"
     done
-    for dir in "${STORAGE_DIRS[@]}"; do
+    for dir in "${APPDATA_DIRS[@]}"; do
         echo "  ├── $dir/"
     done
-    for dir in "${APPDATA_DIRS[@]}"; do
+    for dir in "${BACKUP_DIRS[@]}"; do
         echo "  └── $dir/"
     done
 
@@ -876,7 +868,7 @@ create_folder_structure() {
         return 0
     fi
 
-    for dir in "${USER_DIRS[@]}" "${MEDIA_DIRS[@]}" "${STORAGE_DIRS[@]}" "${APPDATA_DIRS[@]}"; do
+    for dir in "${USER_DIRS[@]}" "${MEDIA_DIRS[@]}" "${APPDATA_DIRS[@]}" "${BACKUP_DIRS[@]}"; do
         mkdir -p "${mount_point}/${dir}"
         log_debug "Created: ${mount_point}/${dir}"
     done
@@ -1232,11 +1224,11 @@ main() {
     echo ""
     echo "    # Immich photo storage"
     echo "    volumes:"
-    echo "      - ${mount_point}/storage/immich:/usr/src/app/upload"
+    echo "      - ${mount_point}/appdata/immich:/usr/src/app/upload"
     echo ""
     echo "    # Nextcloud data"
     echo "    volumes:"
-    echo "      - ${mount_point}/storage/nextcloud:/var/www/html/data"
+    echo "      - ${mount_point}/appdata/nextcloud:/var/www/html/data"
     echo ""
     echo -e "  ${BOLD}Verify mount survives reboot:${NC}"
     echo "    sudo mount -a       # Test fstab now"