feat: Add detailed metadata to node files listing

Enhance the node files API to include comprehensive file metadata:
- File size in bytes
- File creation time (ISO 8601 format)
- File modification time (ISO 8601 format)
- File extension

Create new NodeFile schema to support these additional fields
while keeping the existing ProjectFile schema for backward compatibility.

This provides users with better information to manage and identify
files in the Web UI.

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

gns3server/compute/project.py

@@ -18,6 +18,7 @@ import os
 import shutil
 import asyncio
 import hashlib
+import datetime
 
 from uuid import UUID, uuid4
 from fastapi import HTTPException
@@ -420,10 +421,10 @@ class Project:
 
     async def list_node_files(self, node_path: str):
         """
-        List files in a specific node directory.
+        List files in a specific node directory with detailed metadata.
 
         :param node_path: Relative path to node directory (e.g., "project-files/qemu/node-id")
-        :returns: Array of files in the node directory
+        :returns: Array of files in the node directory with metadata
         """
 
         node_full_path = os.path.normpath(os.path.join(self.path, node_path))
@@ -442,14 +443,37 @@ class Project:
             for filename in os.listdir(node_full_path):
                 file_path = os.path.join(node_full_path, filename)
                 if os.path.isfile(file_path) and not filename.endswith(".ghost"):
-                    file_info = {"path": filename}
                     try:
-                        file_info["md5sum"] = await wait_run_in_executor(
-                            self._hash_file, file_path
+                        # Get file stat information
+                        stat_info = await wait_run_in_executor(os.stat, file_path)
+
+                        # Get file extension
+                        _, extension = os.path.splitext(filename)
+                        extension = extension.lstrip('.')
+
+                        # Format timestamps as ISO 8601
+                        created_at = await wait_run_in_executor(
+                            lambda: datetime.datetime.fromtimestamp(stat_info.st_ctime).isoformat()
                         )
-                    except OSError:
+                        modified_at = await wait_run_in_executor(
+                            lambda: datetime.datetime.fromtimestamp(stat_info.st_mtime).isoformat()
+                        )
+
+                        # Get MD5 checksum
+                        md5sum = await wait_run_in_executor(self._hash_file, file_path)
+
+                        file_info = {
+                            "path": filename,
+                            "md5sum": md5sum,
+                            "size": stat_info.st_size,
+                            "created_at": created_at,
+                            "modified_at": modified_at,
+                            "extension": extension
+                        }
+                        files.append(file_info)
+                    except OSError as e:
+                        log.warning(f"Error getting metadata for file '{filename}': {e}")
                         continue
-                    files.append(file_info)
         except OSError as e:
             log.error(f"Error listing node files: {e}")