task-output-writer wrote to process.cwd()/.sisyphus/task-outputs/ while
council_finalize read from ctx.directory/.sisyphus/task-outputs/. When
these differ, all output files appear missing.
Fix by passing directory to writeTaskOutput from BackgroundManager, and
adding basePath to council_read. Also removes process.chdir() from tests
that was masking the bug.
- council_finalize: batch extract, archive, and return council results
- council_read: secure file reader for archived council responses
- background_wait: stripped to metadata-only, returns completed_tasks array
- Removed all council-specific logic from background_wait
- 28/28 tests passing across all changed files
ismeth