Add error status and messaging

[kleneway]

When JACoB stops work on a task due to an error or retry timeout, we currently only see this information on the GitHub comment. We need to also display this information in the web portal to let the user know what went wrong and provide a link to the Issue or PR where JACoB stopped working.

• [x] Update the core Task type to add an optional statusMessage value
• [x] Add a new Task event to the JACoB core engine when it encounters a blocking error or hits the retry limit
  • [x] Mark the status as TaskStatus.ERROR
  • [x] Add the error message to the statusMessage field
• [ ] Update the getTasks function in the eventsRouter to use the most recent task event from the database and add the status to the output (currently it's dynamically generated based on the GitHub issue status)
• [ ] Update the status section at the bottom of the Workspace component to prominently display the error message and a red error message in case of an error
• [ ] Add a red error icon to the Workspace tab for the task
• [ ] Update the onAdd subscription function in Dashboard.tsx
  • [ ] Update the status to the current task status (currently it assumes the task is done)
  • [ ] Add a toast error notification if a new Task with an error shows up

[cpirich]

This commit generates the TaskStatus.ERROR events: https://github.com/jacob-ai-bot/jacob/commit/d0c4093e5b1f3ac4b78cca139e2cbac9ddae81ce

@kleneway: Note that the TaskSubType field is still incomplete. As a result, we may generate these after failure for a variety of other commands (pull request review, build, create story, etc.) - and the subType will probably be TaskSubType.EDIT_FILES - which isn't particularly correct - nor will this failure event correspond to a previous TaskStatus.IN_PROGRESS event since we don't generate those for many other commands (sub types) yet.