UX: Add confirmation prompt before PBS client installation

Improved the installation flow to be more explicit and user-friendly
when PBS client is not installed on the system.

BEFORE:
- Script immediately started installing
- No clear indication of what would happen
- User couldn't cancel

AFTER:
- Clear message: "Proxmox Backup Client is not installed"
- Shows 3-step plan:
  1. Install Proxmox Backup Client
  2. Configure your first backup target
  3. Set up automated backups
- Asks for confirmation: "Do you want to proceed?"
- User can cancel by entering anything other than "yes"
- Clear progress messages after each step

FLOW:
1. Detect PBS not installed
2. Show what will happen
3. Ask for confirmation
4. Install (if confirmed)
5. Configure first target
6. Exit

The script already correctly skips the multi-target menu when PBS
is not installed - this change just makes the flow more explicit
and gives users control over whether to proceed.

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

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

CHANGELOG.md

@@ -129,6 +129,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - Runs in subshell to avoid environment pollution
 
 ### Changed
+- **Clearer installation flow when PBS client not installed**
+  - Shows what the script will do before proceeding
+  - Lists 3 steps: Install PBS client, Configure target, Set up automation
+  - Asks for confirmation before installation
+  - Allows user to cancel if they change their mind
+  - No menu options shown (install → configure → exit)
+  - Clear progress messages throughout installation
 - **Improved menu flow for viewing target details**
   - "View target details" moved from main menu option 6 to sub-menu under "List all backup targets"
   - After listing targets, users can choose:

pbs-client-installer.sh

@@ -2149,11 +2149,27 @@ main() {
         fi
     else
         # PBS client not installed
+        info "Proxmox Backup Client is not installed on this system"
+        echo
+        echo "This script will:"
+        echo "  1. Install Proxmox Backup Client"
+        echo "  2. Configure your first backup target"
+        echo "  3. Set up automated backups"
+        echo
+
+        PROCEED=$(prompt "Do you want to proceed with installation? (yes/no)" "yes")
+
+        if [ "$PROCEED" != "yes" ]; then
+            info "Installation cancelled"
+            exit 0
+        fi
+
+        echo
         info "Installing Proxmox Backup Client..."
         install_pbs_client
 
         echo
-        info "Let's create your first backup target!"
+        info "Installation complete! Now let's create your first backup target!"
         echo
 
         TARGET_NAME=$(prompt "Enter name for first target (e.g., 'primary', 'local', 'offsite')" "default")