Add formatError() helper that extracts both message and full stack from
unknown caught values, and use it at every status:"failed" catch site in
executor, agent-heartbeat, and triage. Stack traces now land in
store.logEntry outcome (persisted to task.log/activityLog) and in stderr
logger output, so failures like "Cannot read properties of undefined
(reading 'filter')" can be diagnosed without re-running.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
59e270980e