fix(chat-input): stop template dialogs from sending and fix attachment races

- Template dialogs no longer submit the outer chat form
- Sending is blocked while files or URLs are still extracting
- File and URL extraction no longer drop or resurrect entries
- IME composition Enter no longer sends
- Tool call cards show the error text; keyboard handling on cards fixed
- Template import available when empty, edit dialog resets, saved templates refresh
- Only png/jpeg/gif/webp images accepted, SVG sent as text; PDF objects released
- parse-url request sends the access code

components/chat/types.ts

@@ -13,4 +13,5 @@ export interface ToolPartLike {
         operations?: DiagramOperation[]
     } & Record<string, unknown>
     output?: string
+    errorText?: string
 }