Fix --git-since not detecting first file change in filtered directories

The VFS only sets up file watches via read() and read_dir(), not
metadata(). When git filtering caused snapshot_from_vfs to return
early for $path directories, read_dir was never called, so no file
watch was established. This meant file modifications never generated
VFS events and were silently ignored until the server was restarted.

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

src/snapshot_middleware/project.rs

@@ -160,6 +160,16 @@ pub fn snapshot_project_node(
                 .canonicalize(full_path.as_ref())
                 .unwrap_or_else(|_| full_path.to_path_buf());
             metadata.relevant_paths.push(normalized);
+
+            // The VFS only sets up file watches via read() and read_dir(),
+            // not via metadata(). Since the git filter caused snapshot_from_vfs
+            // to return early (before read_dir was called), the VFS is not
+            // watching this path. We must read the directory here to ensure
+            // the VFS sets up a recursive watch, otherwise file change events
+            // will never fire and live sync won't detect modifications.
+            if full_path.is_dir() {
+                let _ = vfs.read_dir(&full_path);
+            }
         }
     }