fix(coding-agent): propagate autocomplete to custom editors (#1372)

setupAutocomplete only sets the provider on defaultEditor. When an
extension customizes the editor via setEditorComponent during
session_start, the custom editor is created before setupAutocomplete
runs, so it never receives the autocomplete provider. This breaks forced
file suggestions, slash commands, and all other completions.

Set the provider on the active editor too when it differs from the
default, covering initial load, reload, and settings changes.

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -359,6 +359,9 @@ export class InteractiveMode {
 			fdPath,
 		);
 		this.defaultEditor.setAutocompleteProvider(this.autocompleteProvider);
+		if (this.editor !== this.defaultEditor) {
+			this.editor.setAutocompleteProvider?.(this.autocompleteProvider);
+		}
 	}
 
 	async init(): Promise<void> {