Three hooks crashed with TypeError when MCP tools returned results where
output.output is undefined. Added type guards to all affected hooks:
- comment-checker/hook.ts: guard before toLowerCase()
- edit-error-recovery/hook.ts: guard before toLowerCase()
- task-resume-info/hook.ts: guard before startsWith()/includes()/trimEnd()
- Added test for undefined output.output in edit-error-recovery
Fixes#1746
