cleanup, docs

site/doc/pages/file_rename.txt

@@ -1,9 +1,20 @@
-file_rename
+:sig
+bool file_rename(String from, String to)
 
-Structural filesystem operation across the wasm host membrane. All path arguments are policy-gated through the same guest file/write roots as other file APIs and return false on denial or OS error.
+:params
+from : source path
+to : destination path
+return value : true on success
+
+:content
+Renames or moves a file. After a successful rename the source path no longer exists. Use it for atomic publish patterns: write a temp file, then rename it into place.
+
+:example
+file_put_contents("/tmp/doc-rename-a.txt", "moved");
+file_rename("/tmp/doc-rename-a.txt", "/tmp/doc-rename-b.txt");
+print(file_get_contents("/tmp/doc-rename-b.txt"), " / source ", file_exists("/tmp/doc-rename-a.txt") ? "exists" : "gone", "\n");
 
 :see
 >sys
-
-:example
-print("file_rename example\n");
+file_copy
+file_temp