docs(changelog): Wave 5 entry for iter 13-26 host-side ADR-110 work

Iter 27 — captures everything that landed since the Wave 4 v0.6.8 entry:
v0.6.9 sync packet emission, v0.7.0 byte-19 bit-4 wire-fix, full Python
+ Rust decoder API parity (25 unit tests), sensing-server consumes
sync packets + applies measured-fps EMA, NodeSyncSnapshot in
WebSocket sensing_update JSON (3 serialization tests), user-guide
"Per-node mesh sync (ADR-110)" section, branch-coordination docs,
1437-test workspace verification baseline.

The CHANGELOG entry references every test count and witness section
so reviewers can trace any claim back to a concrete test or §A0.x log
entry. No more "see commits" — the changelog states the substantive
changes and their evidence.

Co-Authored-By: claude-flow <ruv@ruv.net>

CHANGELOG.md

@@ -78,6 +78,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - **Security fix** (`scripts/redact-secrets.py` + `generate-witness-bundle.sh`): the Python proof step was echoing `.env` contents into the bundled `verification-output.log` via Pydantic validation errors. Bundle nuked before push; added a `stdin -> stdout` redaction filter covering common token prefixes, long opaque strings, and long hex runs. Verified zero leaks on rebuild.
   - **Wave 3 — firmware v0.6.7 (LP-core full + soft-AP HE)**: two software-only unblocks for the hardware-blocked items in WITNESS-LOG-110 §B. (1) **Real LP-core motion-gate program** (`firmware/esp32-csi-node/main/lp_core/main.c` + integration in `c6_lp_core.c`). When `CONFIG_C6_LP_CORE_ENABLE=y`, the LP RISC-V coprocessor now runs a real polling program (configurable cadence via `CONFIG_C6_LP_POLL_PERIOD_US`, default 10 ms) that debounces N consecutive GPIO samples (`CONFIG_C6_LP_DEBOUNCE_SAMPLES`, default 3) and wakes the HP core via `ulp_lp_core_wakeup_main_processor()`. HP entry uses `esp_sleep_enable_ulp_wakeup` + `ESP_SLEEP_WAKEUP_ULP`. Exposes `c6_lp_core_motion_count()` and `c6_lp_core_poll_count()` getters for the witness harness. **Replaces** the v0.6.6 `esp_deep_sleep_enable_gpio_wakeup` ext1 fallback (which floored at ~10 µA, the same as the S3 ULP-FSM). The fallback path stays as the `else` branch so builds without `CONFIG_C6_LP_CORE_ENABLE` keep working unchanged — zero regression for v0.6.6-era fleets. Targets the C6 datasheet ≤5 µA average for battery seed nodes; pending INA/Joulescope measurement to confirm (`WITNESS-LOG-110 §B4`). (2) **Wi-Fi 6 soft-AP with TWT Responder=1** (`c6_softap_he.{h,c}` + `main.c` AP+STA mode switch). When `CONFIG_C6_SOFTAP_HE_ENABLE=y`, one C6 board can act as the iTWT-capable AP the bench is otherwise missing — pair with a second C6-STA board to negotiate real iTWT against a known-cooperative AP and measure deterministic CSI cadence (`WITNESS-LOG-110 §B1/B2`). SSID/PSK/channel configurable via Kconfig defaults or NVS (`softap_ssid`/`softap_psk`/`softap_chan` keys in the `ruview` namespace). Default off so existing nodes are unaffected. **Build artifacts**: S3 8 MB binary 1093 KB (47 % slack), C6 4 MB binary 1019 KB (45 % slack). Tag: `v0.6.7-esp32`.
   - **Wave 4 — firmware v0.6.8 (ESP-NOW mesh offset smoother)**: `c6_sync_espnow.c` now maintains an in-firmware exponential-moving-average of the cross-board sync offset (α = 1/8, fixed-point shift, ≈ 8-sample window at the 10 Hz beacon rate). New getter `c6_sync_espnow_get_offset_us_smoothed()`. `c6_sync_espnow_get_epoch_us()` now returns timestamps stamped from the smoothed offset once seeded — every downstream CSI-frame consumer gets bounded-jitter alignment for free, no host-side filter required. **Measured on the bench**: 5-min two-board soak (WITNESS-LOG-110 §A0.10) drops raw offset stdev 411.5 µs → smoothed 104.1 µs (**3.95× suppression** on stdev, 4.70× on peak-to-peak range) while preserving the +30 µs/min crystal-drift trajectory within 2 µs/min. **The ADR-110 §2.4 ≤100 µs multistatic alignment target that v0.6.6 designed is now empirically measured, not just stated.** Cross-board beacon match rate 99.56% over 5 min, 0 TX failures. Binary cost: +32 bytes (one int64, one bool, one getter). Diag log adds `smoothed=…` field. Tag: `v0.6.8-esp32`. **Known wiring gap (deferred)**: `csi_serialize_frame` does not yet stamp frames with `c6_sync_espnow_get_epoch_us()` — the ADR-018 frame format has no timestamp field, and adding one is a breaking change that needs an ADR update. Multistatic CSI fusion will require either an ADR-018 v2 with timestamp, or a separate UDP sync packet keyed off the existing flag bit. Tracked in WITNESS-LOG-110 §A0.11.
+  - **Wave 5 — firmware v0.6.9 + v0.7.0 + host wiring (loop iter 8 → iter 26)**: closes the §A0.11 gap and lights up the substrate end-to-end across firmware → host → JSON broadcast. **Firmware**: (a) **v0.6.9-esp32** — `csi_collector.c` emits a 32-byte UDP sync packet (magic `0xC511A110`, distinct from CSI frame magic `0xC5110001`) every `CONFIG_C6_SYNC_EVERY_N_FRAMES` (default 20) CSI frames, carrying `node_id`, `local_us`, mesh-aligned `epoch_us` (from the Wave 4 smoothed offset), and the CSI sequence high-water for host-side pairing. Same UDP socket as CSI; host dispatches by leading magic. Operator-tunable cadence via the new Kconfig knob — N=1 (10 Hz) for tight multistatic, N=200 (~20 s) for low-power seeds. Live-verified on COM9+COM12 (§A0.12): follower reports `local − epoch = 1 163 565 µs`, matches the §A0.10 boot-delta measurement within 285 µs of WiFi MAC TX jitter. (b) **v0.7.0-esp32** — `csi_collector.c:221` ADR-018 byte 19 bit 4 ("cross-node sync valid") now ORs in `c6_sync_espnow_is_valid()` so frames from sync'd ESP-NOW nodes correctly advertise sync (previously only sourced from the broken 802.15.4 path — false-negative bug, §A0.13). Side effect: S3 boards now also set the bit since `c6_sync_espnow` is cross-target. **Host decoders + 25 unit tests**: Python `SyncPacketParser` + `SyncPacket` dataclass with `apply_to_local` / `mesh_aligned_us_for_sequence` / `local_minus_epoch_us` (10 tests in `TestSyncPacketParser`); Rust `wifi_densepose_hardware::SyncPacket` + `SyncPacketFlags` + `SYNC_PACKET_MAGIC` re-exported from the crate root with identical API surface (15 tests in `sync_packet::tests`). **Cross-language conformance gate** (loop iter 21): the same 32-byte canonical hex `10a111c509010600f26db70100000000c5aca501000000001400000000000000` is pinned in both test suites; if either decoder drifts from the wire, exactly one named test fires and points at the moved side. **Sensing-server wiring**: `udp_receiver_task` magic-dispatches `0xC511A110` and stores per-node `latest_sync: Option<SyncPacket>` + `latest_sync_at: Option<Instant>` on `NodeState`. New helpers: `NodeState::mesh_aligned_us(local_us)`, `NodeState::mesh_aligned_us_for_csi_frame(sequence)` (uses the per-node measured fps EMA with 5-sample warmup + 9 s staleness gate), `NodeState::observe_csi_frame_arrival(now)` (feeds `update_csi_fps_ema` α=1/8, called once per accepted CSI frame). 4 fps-EMA tests + 3 NodeSyncSnapshot serialization tests on the binary target. **Public JSON API**: `sensing_update` broadcasts now carry an optional `sync` object per node — `{offset_us, is_leader, is_valid, smoothed, sequence, csi_fps_ema, csi_fps_samples}` — `#[serde(skip_serializing_if = "Option::is_none")]` so non-mesh paths (multi-BSSID scan / synthetic-RSSI fallback / simulation) omit the key entirely. Existing pre-v0.7.0 UI clients ignore it cleanly. Documented in `docs/user-guide.md` "Per-node mesh sync (ADR-110)" section with field table, UI rendering rules, and the timestamp-recovery recipe. **Branch-coordination**: `docs/ADR-110-BRANCH-STATE.md` maps which files each of `adr-110-esp32c6` vs `feat/adr-115-ha-mqtt-matter` touches (regions are disjoint, merges should be clean line-merges). **Verification baselines**: full v2 cargo workspace at **1437 tests passing** (no regression across 17 crate batches), full `wifi-densepose-hardware` crate at **137 tests**. ADR-110 §B substrate is now end-to-end visible to UI clients and ready for ADR-029/030 multistatic CSI fusion consumption.
 - **Real-time CSI introspection / low-latency tap on `wifi-densepose-sensing-server` (ADR-099).**
   New `wifi_densepose_sensing_server::introspection` module wires
   [midstream](https://github.com/ruvnet/midstream)'s `temporal-attractor` (Lyapunov +