implement headless sync plugin

src/shims/fs/index.js

@@ -49,4 +49,20 @@ export const fsShim = {
     metadataCache.populate(tree);
     console.log(`[shim:fs] Initialized with ${metadataCache.size} entries`);
   },
+
+  async _refreshSubtree(subPath) {
+    const tree = await transport.fetchTree(subPath);
+    const prefix = subPath.replace(/\\/g, "/").replace(/^\/+/, "").replace(/\/+$/, "");
+
+    // Tree keys are relative to subPath, so prefix them to make vault-relative
+    const prefixed = {};
+
+    prefixed[prefix] = { type: "directory" };
+
+    for (const [key, meta] of Object.entries(tree)) {
+      prefixed[prefix + "/" + key] = meta;
+    }
+
+    metadataCache.merge(prefixed);
+  },
 };

src/shims/fs/metadata-cache.js

@@ -82,6 +82,13 @@ export class MetadataCache {
     return results;
   }
 
+  // Merge entries from a subtree without clearing existing data
+  merge(tree) {
+    for (const [path, meta] of Object.entries(tree)) {
+      this._entries.set(this._normalize(path), meta);
+    }
+  }
+
   get size() {
     return this._entries.size;
   }