Strategies show pending, ready, or failed status

If strategy creation errored partway through, the broken strategy still appeared in your list looking exactly like a working one. Clicking it would surface the failure, but only after you'd already tried to use it. Not great.

Every strategy now carries one of three statuses: pending (still being built), ready (backtested at least once), or failed (creation hit an error and never recovered). The list view shows a small status pill on each row, failed strategies are visually de-emphasised, and the row links to the underlying error rather than pretending it ran.

Same idea as the wallet fix below: when something is broken, say so. The whole point of the strategy agent is to be a trustworthy collaborator, and trust evaporates fast when broken work looks identical to working work.