#10996: fix(control-ui): hide tool call blocks when thinking/working toggle is off

## Summary Fixes #10985 The "Toggle assistant thinking/working output" button in the Control UI only hides tool **result** messages (role `toolResult`), but does not hide assistant messages whose content consists solely of tool **call** items (`toolcall`, `tool_use`, etc.) with no user-visible text. This causes tool call blocks (showing tool name + "Completed" status) to remain visible even when the toggle is off. ## Changes ### `ui/src/ui/chat/message-normalizer.ts` - Added `isToolOnlyMessage()` helper that detects messages that are purely tool-related: - Messages with role `toolresult` / `tool_result` - Messages with `toolCallId` or `tool_call_id` - Messages whose content array contains only tool call/result type items (with no meaningful text) - Thinking blocks are ignored (not considered user-visible text) ### `ui/src/ui/views/chat.ts` - Replaced the narrow `role === "toolresult"` check in `buildChatItems()` with the new `isToolOnlyMessage()` helper ### `ui/src/ui/chat/message-normalizer.test.ts` - Added comprehensive tests for `isToolOnlyMessage()` covering all edge cases ## Expected Behavior When the toggle is OFF, only clean assistant text is displayed. Tool call blocks like `sessions_spawn Completed` or `exec Completed` are hidden. <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> - Adds `isToolOnlyMessage()` to classify messages that are purely tool-call/result related (ignoring empty text + thinking blocks). - Uses this helper in `ui/src/ui/views/chat.ts` to hide tool-only blocks when the “show thinking/working” toggle is off. - Extends `message-normalizer.test.ts` with coverage for tool-only classification edge cases. <h3>Confidence Score: 3/5</h3> - This PR is close to safe to merge, but the current tool-only detection can hide legitimate assistant text in some message shapes. - Main behavioral change is localized and well-tested, but `isToolOnlyMessage()` treats the presence of `toolCallId`/`tool_call_id` as sufficient to hide a message when the toggle is off. If any assistant messages include user-visible text alongside a toolCallId, those messages will incorrectly disappear. - ui/src/ui/chat/message-normalizer.ts, ui/src/ui/views/chat.ts <!-- greptile_other_comments_section --> _{(3/5) Reply to the agent's comments like "Can you suggest a fix for this @greptileai?" or ask follow-up questions!} <!-- /greptile_comment -->