Add tool call error reporting

Unsure about this one. It would also be good UX to include a "report" button or something when this happens, and have that create a github issue / send a slack message / whatever system you use.

Review the screenshot and the tool-call error experience described in issue #134. Clarify whether the goal is only error reporting or also a report button, and choose the reporting destination before implementation. Done should include an agreed reporting flow and a clear way to verify that tool-call errors can be reported.

Written by the indexing model from the issue text.