fix: resolve relative paths in folder browser, add placeholders help modal

- browseDir() now resolves paths via BackupDirectory::resolve() before
  permission check, fixing "access denied" when browsing from [DEFAULT_DIR]
- SQL default for backup_dir changed to [DEFAULT_DIR] placeholder
- Added help button (?) next to Browse that opens a modal listing all
  available placeholders with examples and recommended paths

source/packages/com_mokosuitebackup/sql/install.mysql.sql

@@ -6,7 +6,7 @@ CREATE TABLE IF NOT EXISTS `#__mokosuitebackup_profiles` (
 	`archive_format`    VARCHAR(10) NOT NULL DEFAULT 'zip',
 	`compression_level` TINYINT(1) UNSIGNED NOT NULL DEFAULT 5 COMMENT '0=none, 9=max',
 	`split_size`        INT(11) UNSIGNED NOT NULL DEFAULT 0 COMMENT '0=no split, otherwise MB per part',
-	`backup_dir`        VARCHAR(512) NOT NULL DEFAULT 'administrator/components/com_mokosuitebackup/backups',
+	`backup_dir`        VARCHAR(512) NOT NULL DEFAULT '[DEFAULT_DIR]',
 	`archive_name_format` VARCHAR(512) NOT NULL DEFAULT '[host]_[datetime]_profile[profile_id]' COMMENT 'Filename format with placeholders',
 	`exclude_dirs`      TEXT NOT NULL COMMENT 'Newline-separated directory paths to exclude',
 	`exclude_files`     TEXT NOT NULL COMMENT 'Newline-separated filename patterns to exclude',
@@ -81,7 +81,7 @@ INSERT IGNORE INTO `#__mokosuitebackup_profiles` (
 	`published`, `ordering`, `created`, `modified`
 ) VALUES (
 	1, 'Default Backup Profile', 'Full site backup with default settings', 'full',
-	'zip', 5, 0, 'administrator/components/com_mokosuitebackup/backups',
+	'zip', 5, 0, '[DEFAULT_DIR]',
 	'administrator/components/com_mokosuitebackup/backups\ntmp\ncache\nlogs\nadministrator/logs',
 	'.gitignore\n.htaccess.bak',
 	'#__session',

source/packages/com_mokosuitebackup/src/Controller/AjaxController.php

@@ -82,7 +82,10 @@ class AjaxController extends BaseController
 		}
 
 		$requestPath = $this->input->getString('path', JPATH_ROOT);
-		$path = realpath($requestPath) ?: $requestPath;
+
+		// Resolve placeholders and relative paths before permission check
+		$resolved = BackupDirectory::resolve($requestPath);
+		$path = realpath($resolved) ?: $resolved;
 
 		// Security: restrict browsing to site root and current user's home
 		$jRoot   = realpath(JPATH_ROOT);

source/packages/com_mokosuitebackup/src/Field/FolderPickerField.php

@@ -96,6 +96,9 @@ class FolderPickerField extends FormField
 		<span class="icon-folder-open" aria-hidden="true"></span>
 		Browse
 	</button>
+	<button type="button" class="btn btn-outline-info" data-bs-toggle="modal" data-bs-target="#{$id}_helpModal" title="Available placeholders">
+		<span class="icon-question-circle" aria-hidden="true"></span>
+	</button>
 </div>
 <div class="mt-1" id="{$id}_status">
 	<small class="{$statusClass}">
@@ -107,6 +110,44 @@ class FolderPickerField extends FormField
 	<span class="icon-warning-circle" aria-hidden="true"></span>
 	The default backup directory is inside the web root. Backup archives may be directly downloadable if <code>.htaccess</code> is not supported. For better security, use a path outside the web root.
 </div>
+<div class="modal fade" id="{$id}_helpModal" tabindex="-1" aria-labelledby="{$id}_helpLabel" aria-hidden="true">
+	<div class="modal-dialog">
+		<div class="modal-content">
+			<div class="modal-header">
+				<h5 class="modal-title" id="{$id}_helpLabel">Backup Directory Placeholders</h5>
+				<button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
+			</div>
+			<div class="modal-body">
+				<p>Use these placeholders in the backup directory path. They are resolved at backup time.</p>
+				<table class="table table-sm table-striped">
+					<thead><tr><th>Placeholder</th><th>Description</th><th>Example</th></tr></thead>
+					<tbody>
+						<tr><td><code>[HOME]</code></td><td>Home directory of the server user</td><td><code>{$placeholders['[HOME]']}</code></td></tr>
+						<tr><td><code>[DEFAULT_DIR]</code></td><td>Default backup directory (inside web root)</td><td><code>{$placeholders['[DEFAULT_DIR]']}</code></td></tr>
+						<tr><td><code>[host]</code></td><td>Server hostname</td><td><code>{$placeholders['[host]']}</code></td></tr>
+						<tr><td><code>[site_name]</code></td><td>Joomla site name</td><td><code>{$placeholders['[site_name]']}</code></td></tr>
+						<tr><td><code>[date]</code></td><td>Date (Ymd)</td><td><code>{$placeholders['[date]']}</code></td></tr>
+						<tr><td><code>[year]</code></td><td>Four-digit year</td><td><code>{$placeholders['[year]']}</code></td></tr>
+						<tr><td><code>[month]</code></td><td>Two-digit month</td><td><code>{$placeholders['[month]']}</code></td></tr>
+						<tr><td><code>[day]</code></td><td>Two-digit day</td><td><code>{$placeholders['[day]']}</code></td></tr>
+						<tr><td><code>[profile_id]</code></td><td>Backup profile ID</td><td><code>1</code></td></tr>
+						<tr><td><code>[profile_name]</code></td><td>Profile title</td><td><code>default</code></td></tr>
+						<tr><td><code>[type]</code></td><td>Backup type</td><td><code>full</code></td></tr>
+					</tbody>
+				</table>
+				<h6>Recommended Paths</h6>
+				<ul class="list-unstyled">
+					<li><code>[HOME]/backups</code> — Outside web root (recommended)</li>
+					<li><code>[HOME]/backups/[host]</code> — Per-site subdirectory</li>
+					<li><code>[DEFAULT_DIR]</code> — Inside web root (protected by .htaccess)</li>
+				</ul>
+			</div>
+			<div class="modal-footer">
+				<button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Close</button>
+			</div>
+		</div>
+	</div>
+</div>
 <div id="{$id}_browser" class="card mt-2" style="display:none; max-height:300px; overflow-y:auto;">
 	<div class="card-body p-2">
 		<div id="{$id}_tree"></div>