Add capture() to spawn, add rsync itemize parser

lib/itemize.js

@@ -0,0 +1,56 @@
+/**
+ * Parse rsync --itemize-changes output into a structured change list.
+ *
+ * rsync itemize format: 11-character code + space + path
+ *
+ * Code structure: YXcstpoguax
+ *   Y = update type: > (transfer), * (message/delete), c (local change), . (no update), h (hard link)
+ *   X = file type:   f (file), d (dir), L (symlink), D (device), S (special)
+ *   remaining chars = what changed (size, time, perms, etc.) or '+++++++++' for new
+ *
+ * We care about:
+ *   >f... = file transferred (new or modified)
+ *   *deleting = file deleted
+ *   cd... = directory (ignored for delta purposes)
+ */
+
+/**
+ * @typedef {{ status: 'added'|'modified'|'deleted', path: string }} Change
+ */
+
+/**
+ * Parse rsync --itemize-changes stdout into a list of file changes.
+ * @param {string} output
+ * @returns {Change[]}
+ */
+export function parseItemize(output) {
+  const changes = [];
+
+  for (const raw of output.split('\n')) {
+    const line = raw.trimEnd();
+    if (!line) continue;
+
+    // Deleted files: "*deleting   path/to/file"
+    if (line.startsWith('*deleting ')) {
+      const path = line.slice('*deleting '.length).trimStart();
+      // Skip directory deletions (trailing slash)
+      if (!path.endsWith('/')) {
+        changes.push({ status: 'deleted', path });
+      }
+      continue;
+    }
+
+    // File transfers: ">f......... path" (new or modified)
+    if (line.length > 12 && line[0] === '>' && line[1] === 'f') {
+      const code = line.slice(0, 11);
+      const path = line.slice(12);
+      const isNew = code.slice(2) === '+++++++++';
+      changes.push({ status: isNew ? 'added' : 'modified', path });
+      continue;
+    }
+
+    // Everything else (dirs, symlinks, attribute-only changes) — ignore
+  }
+
+  return changes;
+}