refactor(extensions): add public update() method to ExtensionRegistry

Add a proper public API for updating registry metadata while preserving
installed_at timestamp, instead of directly mutating internal registry
data and calling private _save() method.

Changes:
- Add ExtensionRegistry.update() method that preserves installed_at
- Update enable/disable commands to use registry.update()
- Update rollback logic to use registry.update()

This decouples the CLI from registry internals and maintains proper
encapsulation.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: iamaeroplane

src/specify_cli/__init__.py

@@ -2839,8 +2839,7 @@ def extension_update(
 
                     # Restore registry entry
                     if backup_registry_entry:
-                        manager.registry.data["extensions"][extension_id] = backup_registry_entry
-                        manager.registry._save()
+                        manager.registry.update(extension_id, backup_registry_entry)
 
                     console.print(f"   [green]✓[/green] Rollback successful")
                 except Exception as rollback_error:
@@ -2895,9 +2894,7 @@ def extension_enable(
         raise typer.Exit(0)
 
     metadata["enabled"] = True
-    # Update registry directly to preserve installed_at (add() would overwrite it)
-    manager.registry.data["extensions"][extension_id] = metadata
-    manager.registry._save()
+    manager.registry.update(extension_id, metadata)
 
     # Enable hooks in extensions.yml
     config = hook_executor.get_project_config()
@@ -2941,9 +2938,7 @@ def extension_disable(
         raise typer.Exit(0)
 
     metadata["enabled"] = False
-    # Update registry directly to preserve installed_at (add() would overwrite it)
-    manager.registry.data["extensions"][extension_id] = metadata
-    manager.registry._save()
+    manager.registry.update(extension_id, metadata)
 
     # Disable hooks in extensions.yml
     config = hook_executor.get_project_config()

src/specify_cli/extensions.py

@@ -228,6 +228,25 @@ def add(self, extension_id: str, metadata: dict):
         }
         self._save()
 
+    def update(self, extension_id: str, metadata: dict):
+        """Update extension metadata in registry, preserving installed_at.
+
+        Use this method instead of add() when updating existing extension
+        metadata (e.g., enabling/disabling) to preserve the original
+        installation timestamp.
+
+        Args:
+            extension_id: Extension ID
+            metadata: Extension metadata to update
+
+        Raises:
+            KeyError: If extension is not installed
+        """
+        if extension_id not in self.data["extensions"]:
+            raise KeyError(f"Extension '{extension_id}' is not installed")
+        self.data["extensions"][extension_id] = metadata
+        self._save()
+
     def remove(self, extension_id: str):
         """Remove extension from registry.