Activate Proxmox auto-installer by bypassing file-existence gate in GRUB config

The auto-installer menuentry was wrapped in 'if [ -f auto-installer-mode.toml ]'
which never evaluated true. Replace the condition with 'if true' to activate the
built-in auto-installer entry, and only add the answer-url to kernel lines that
already have proxmox-start-auto-installer (rather than modifying the graphical
install entry).

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

internal/image/isomod.go

@@ -109,42 +109,41 @@ func rewriteGrubConfig(original, answerURL string) string {
 	lines := strings.Split(original, "\n")
 	var result []string
 	depth := 0
-	firstMenuModified := false
 
 	for _, line := range lines {
 		trimmed := strings.TrimSpace(line)
 
-		// Strip comments to reclaim space for added kernel parameters
 		if strings.HasPrefix(trimmed, "#") {
 			continue
 		}
 
+		// Activate auto-installer mode by bypassing the file-existence check
+		if strings.Contains(line, "auto-installer-mode.toml") {
+			if strings.Contains(line, "! -f") {
+				line = strings.Replace(line, "[ ! -f auto-installer-mode.toml ]", "false", 1)
+			} else {
+				line = strings.Replace(line, "[ -f auto-installer-mode.toml ]", "true", 1)
+			}
+			trimmed = strings.TrimSpace(line)
+		}
+
 		if strings.HasPrefix(trimmed, "set timeout=") {
 			result = append(result, "set timeout=0")
 			continue
 		}
-		if strings.HasPrefix(trimmed, "set default=") {
-			result = append(result, "set default=0")
-			continue
-		}
 
 		if strings.HasPrefix(trimmed, "menuentry") {
 			depth++
 		}
 		if trimmed == "}" && depth > 0 {
-			if depth == 1 {
-				firstMenuModified = true
-			}
 			depth--
 		}
 
-		if depth > 0 && !firstMenuModified &&
-			(strings.HasPrefix(trimmed, "linux ") || strings.HasPrefix(trimmed, "linux\t")) {
-			if !strings.Contains(line, "proxmox-start-auto-installer") {
-				line = strings.TrimRight(line, " \t") + " proxmox-start-auto-installer"
-			}
-			if answerURL != "" && !strings.Contains(line, "proxmox-auto-installer-answer-url") {
-				line += " proxmox-auto-installer-answer-url=" + answerURL
+		// Add answer URL to kernel lines that already have proxmox-start-auto-installer
+		if depth > 0 && (strings.HasPrefix(trimmed, "linux ") || strings.HasPrefix(trimmed, "linux\t")) {
+			if strings.Contains(line, "proxmox-start-auto-installer") &&
+				answerURL != "" && !strings.Contains(line, "proxmox-auto-installer-answer-url") {
+				line = strings.TrimRight(line, " \t") + " proxmox-auto-installer-answer-url=" + answerURL
 			}
 		}
 
@@ -152,7 +151,6 @@ func rewriteGrubConfig(original, answerURL string) string {
 		result = append(result, line)
 	}
 
-	// Collapse consecutive blank lines
 	var collapsed []string
 	prevBlank := false
 	for _, line := range result {