Let a sync window take a whole share in one click

The window editor is path-first, which is exact but slow for the case that is nearly all of them.
The chips only offer whole shares; a subpath already in the window marks its share partial rather
than offering to widen it, and the path box stays the only way to express a subpath or a profile.

Plugin/unraid/api/rsync.php

@@ -91,6 +91,38 @@ require_once dirname(__DIR__) . '/include/monitor.php';
 
 // ── Live sync log ─────────────────────────────────────────────────────────────
 $action  = $_GET['action'] ?? '';
+// ── Share list, for the quick-select strip on the window editor ──────────────────────────────
+// The editor is path-first — type or browse, then Add — which is exact but slow for the case that
+// is nearly all of them: add one whole share. This answers "what shares exist here", so the strip
+// can offer them as one click each.
+//
+// Read from /boot/config/shares/*.cfg rather than by listing /mnt/user, because a share is a
+// declared thing: the directory can be absent on a share that has never been written to, and
+// listing the mount would also invent entries for stray directories that are not shares at all.
+if ($action === 'shares') {
+    $out = [];
+    foreach (glob('/boot/config/shares/*.cfg') ?: [] as $cfg) {
+        $name = basename($cfg, '.cfg');
+        $raw  = (string) @file_get_contents($cfg);
+        $get  = function (string $k) use ($raw): string {
+            return preg_match('/^' . $k . '="([^"]*)"/m', $raw, $m) ? $m[1] : '';
+        };
+        $path = '/mnt/user/' . $name;
+        $out[] = [
+            'name'    => $name,
+            'path'    => $path,
+            'comment' => $get('shareComment'),
+            'pool'    => $get('shareCachePool'),
+            'cache'   => $get('shareUseCache'),
+            // Present is not the same as declared — a share can exist in conf with no directory yet.
+            'exists'  => is_dir($path),
+        ];
+    }
+    usort($out, fn($a, $b) => strcasecmp($a['name'], $b['name']));
+    header('Content-Type: application/json');
+    echo json_encode(['ok' => true, 'shares' => $out]);
+    exit;
+}
 if ($action === 'rsync_log') {
     $lockDir = '/tmp/unraid_locks';
     $lines   = [];