Add Phase 6 completion notes for bf-64s

Verifies test_stop_hook_fires and test_missing_transcript_path_derived pass;
documents the FIFO open race resolution (OQ-4) and path derivation algorithm.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

notes/bf-64s.md

@@ -0,0 +1,22 @@
+# Phase 6: Stop Poller (bf-64s) — Verification
+
+Phase 6 was implemented in commit `59e170e` (Implement Phase 6: Stop Poller).
+
+## What was implemented
+
+- `src/poller.rs`: `open_fifo_nonblock`, `parse_stop_payload`, `resolve_stop_info`, `derive_transcript_path`, `cwd_to_slug`
+- `src/event_loop.rs`: `add_fifo_fd` and FIFO POLLIN handling in the poll loop
+- `tests/stop_poller.rs`: `test_stop_hook_fires` and `test_missing_transcript_path_derived`
+
+## Test results
+
+Both Phase 6 completion criteria tests passed on CI (iad-ci):
+
+- `test_stop_hook_fires` — mock Stop payload written to FIFO, EventLoop returns FifoPayload, fields extracted correctly
+- `test_missing_transcript_path_derived` — omitted `transcript_path` triggers slug derivation: `/home/user/myproject` → `home-user-myproject`
+
+## Notes
+
+OQ-2 (`--setting-sources=` suppression) and OQ-4 (FIFO open race) are validated:
+- OQ-4: `open_fifo_nonblock` test confirms read-end + keeper-write-end approach prevents ENXIO
+- OQ-2 resolution is handled in `cli.rs` via `--setting-sources=` forwarding when `--no-inherit-hooks` is set