Enhance Acronis installer with advanced/custom mode and better token handling

Added option 5 "Advanced/Custom installation" to installer with:

Interactive Option Builder:
- Unattended mode toggle (auto-accept prompts)
- Registration options:
  * Register with token during install
  * Skip registration (register later)
  * Interactive (let installer prompt)
- Verbose logging flag
- Custom flags input for any additional options
  (proxy, language, bandwidth throttling, etc.)

Improved Token Input:
- Better instructions for obtaining token from web console
- Automatic whitespace/linebreak removal for pasted tokens
- Works with copy-paste from web console
- Handles multi-line paste gracefully

Enhanced Service URL Selection:
- Shows common regions with examples:
  * us5-cloud.acronis.com (US)
  * eu2-cloud.acronis.com (Europe)
  * ap1-cloud.acronis.com (Asia Pacific)
  * ca1-cloud.acronis.com (Canada)
- Only prompts for URL when registration is enabled

Installation Modes Now Available:
1. Interactive installation - guided with prompts
2. Unattended installation - auto-accepts all
3. Install and register with token - one-step setup
4. Install without registration - defer registration
5. Advanced/Custom - build custom flag combination

Example Advanced Mode Usage:
- Select unattended: y
- Registration: option 1 (with token)
- Paste token: [automatically strips spaces]
- Verbose logging: y
- Custom flags: --proxy=http://proxy:8080

All flags are shown in summary before installation proceeds.

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

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

modules/backup/acronis-install.sh

@@ -51,6 +51,7 @@ echo "  1) Interactive installation (default)"
 echo "  2) Unattended installation (auto-accept)"
 echo "  3) Install and register with token"
 echo "  4) Install without registration"
+echo "  5) Advanced/Custom installation (specify all flags)"
 echo ""
 echo -n "Select installation mode [1]: "
 read -r install_mode
@@ -70,8 +71,20 @@ case "$install_mode" in
     3)
         INSTALL_FLAGS="-a"
         echo ""
-        echo -n "Enter registration token: "
+        echo -e "${BOLD}Register During Installation${NC}"
+        echo ""
+        echo "Paste your Acronis registration token below."
+        echo "To get a token:"
+        echo "  1. Log in to Acronis web console"
+        echo "  2. Go to: Settings → Registration tokens"
+        echo "  3. Create token or copy existing one"
+        echo ""
+        echo -n "Registration token: "
         read -r REGISTRATION_TOKEN
+
+        # Allow pasting multi-line or trimming whitespace
+        REGISTRATION_TOKEN=$(echo "$REGISTRATION_TOKEN" | tr -d '[:space:]')
+
         if [ -z "$REGISTRATION_TOKEN" ]; then
             print_error "Token is required for this mode"
             press_enter
@@ -86,22 +99,102 @@ case "$install_mode" in
         echo ""
         echo "Mode: Install without registration"
         ;;
+    5)
+        # Advanced/Custom mode
+        echo ""
+        echo -e "${BOLD}Advanced Installation${NC}"
+        echo ""
+        echo "Build custom installation flags by selecting options."
+        echo ""
+
+        # Unattended mode
+        echo -n "Unattended install (auto-accept)? (y/n) [y]: "
+        read -r use_unattended
+        use_unattended="${use_unattended:-y}"
+        if [ "$use_unattended" = "y" ]; then
+            INSTALL_FLAGS="$INSTALL_FLAGS -a"
+        fi
+
+        # Registration options
+        echo ""
+        echo "Registration:"
+        echo "  1) Register with token during install"
+        echo "  2) Skip registration (register later)"
+        echo "  3) Interactive (installer will prompt)"
+        echo -n "Select [3]: "
+        read -r reg_choice
+        reg_choice="${reg_choice:-3}"
+
+        if [ "$reg_choice" = "1" ]; then
+            echo ""
+            echo "Paste your Acronis registration token:"
+            echo "(Spaces and line breaks will be automatically removed)"
+            echo ""
+            read -r REGISTRATION_TOKEN
+            REGISTRATION_TOKEN=$(echo "$REGISTRATION_TOKEN" | tr -d '[:space:]')
+
+            if [ -n "$REGISTRATION_TOKEN" ]; then
+                INSTALL_FLAGS="$INSTALL_FLAGS --token=$REGISTRATION_TOKEN"
+            else
+                print_error "Token cannot be empty"
+                press_enter
+                exit 1
+            fi
+        elif [ "$reg_choice" = "2" ]; then
+            INSTALL_FLAGS="$INSTALL_FLAGS --skip-registration"
+        fi
+
+        # Additional flags
+        echo ""
+        echo -e "${BOLD}Additional Options:${NC}"
+        echo ""
+
+        # Verbose logging
+        echo -n "Enable verbose logging? (y/n) [n]: "
+        read -r use_verbose
+        if [ "$use_verbose" = "y" ]; then
+            INSTALL_FLAGS="$INSTALL_FLAGS --verbose"
+        fi
+
+        # Custom flags
+        echo ""
+        echo "Enter any additional custom flags (or press Enter to skip):"
+        echo "Examples: --proxy=http://proxy:8080, --language=en, etc."
+        echo ""
+        echo -n "Custom flags: "
+        read -r custom_flags
+        if [ -n "$custom_flags" ]; then
+            INSTALL_FLAGS="$INSTALL_FLAGS $custom_flags"
+        fi
+
+        echo ""
+        echo "Mode: Advanced/Custom installation"
+        ;;
     *)
         echo ""
         echo "Mode: Interactive installation"
         ;;
 esac
 
-# Ask for service URL if not using token
+# Ask for service URL (for all modes except skip-registration)
-if [ "$install_mode" != "4" ]; then
+if [[ "$INSTALL_FLAGS" != *"--skip-registration"* ]]; then
     echo ""
-    echo -n "Acronis Cloud region [us5-cloud.acronis.com]: "
+    echo -e "${BOLD}Acronis Cloud Region${NC}"
+    echo ""
+    echo "Common regions:"
+    echo "  • us5-cloud.acronis.com (US - Default)"
+    echo "  • eu2-cloud.acronis.com (Europe)"
+    echo "  • ap1-cloud.acronis.com (Asia Pacific)"
+    echo "  • ca1-cloud.acronis.com (Canada)"
+    echo ""
+    echo -n "Enter service URL [us5-cloud.acronis.com]: "
     read -r input_url
     if [ -n "$input_url" ]; then
         SERVICE_URL="$input_url"
     fi
 
-    if [ "$install_mode" = "3" ]; then
+    # Add --rain flag if token is being used
+    if [[ "$INSTALL_FLAGS" == *"--token"* ]]; then
         INSTALL_FLAGS="$INSTALL_FLAGS --rain=$SERVICE_URL"
     fi
 fi