confirmed LB-1 is complete

Author: rocketmark

docs/arrows/index.yaml

@@ -1,5 +1,5 @@
 schema_version: 1
-last_updated: 2026-04-13
+last_updated: 2026-04-17
 
 arrows:
   lighthouse-protocol-intelligence:

docs/arrows/lighthouse-protocol-intelligence.md

@@ -15,7 +15,7 @@ Decodes raw photon timestamps into calibrated sweep angles and lighthouse calibr
 - [docs/llds/lighthouse-protocol-intelligence.md](../llds/lighthouse-protocol-intelligence.md)
 
 ### EARS
-- [docs/specs/lighthouse-protocol-intelligence-specs.md](../specs/lighthouse-protocol-intelligence-specs.md) (33 specs)
+- [docs/specs/lighthouse-protocol-intelligence-specs.md](../specs/lighthouse-protocol-intelligence-specs.md) (40 specs)
 
 ### Tests
 - src/test_cases/watchman.c
@@ -56,9 +56,10 @@ Decodes raw photon timestamps into calibrated sweep angles and lighthouse calibr
 | Gen2 LFSR | LPI-PROC-030 to 032 | 2 | 1 | 0 |
 | Angle computation | LPI-PROC-040 to 042 | 3 | 0 | 0 |
 | Sensor activation filtering | LPI-PROC-050 to 053 | 4 | 0 | 0 |
+| Back-face normal filter | LPI-PROC-060 to 066 | 7 | 0 | 0 |
 | Reprojection model | LPI-DATA-060 to 063 | 4 | 0 | 0 |
 
-**Summary:** 29 of 33 specs implemented; 3 active gaps; 0 deferred.
+**Summary:** 36 of 40 specs implemented; 3 active gaps; 0 deferred.
 
 ## Key Findings
 

docs/launch-readiness-triage.2026-04-17.md

@@ -19,11 +19,10 @@
 
 Each item either (a) lets bad data through without visibility, or (b) makes on-set incident response harder because docs/specs don't match reality.
 
-- [ ] **LB-1 — Close spec drift on back-face filter** (`LPI-PROC-060` through `LPI-PROC-066`)
+- [x] **LB-1 — Close spec drift on back-face filter** (`LPI-PROC-060` through `LPI-PROC-066`)
   - Category: **coherence / operational safety**
-  - Feature deployed to both Pis with `--filter-normal-facingness 0.1`. Seven specs in [lighthouse-protocol-intelligence-specs.md](specs/lighthouse-protocol-intelligence-specs.md) still marked `[ ]`.
-  - Fix: mark `[x]`, update [lighthouse-protocol-intelligence.md](arrows/lighthouse-protocol-intelligence.md) arrow-doc coverage table.
-  - Risk if skipped: on-set grep "is the back-face filter in?" returns "not implemented" during a 3am incident.
+  - Feature deployed to both Pis with `--filter-normal-facingness 0.1`. Verified implemented in `src/survive_sensor_activations.c:139-183` (2026-04-17). All 7 specs marked `[x]` in [lighthouse-protocol-intelligence-specs.md](specs/lighthouse-protocol-intelligence-specs.md).
+  - Arrow-doc coverage table still needs updating in [lighthouse-protocol-intelligence.md](arrows/lighthouse-protocol-intelligence.md).
 
 - [ ] **LB-2 — Verify GSS solve-failure rejection** (`DDS-BE-054`)
   - Category: **fail-closed on calibration corruption**

docs/specs/lighthouse-protocol-intelligence-specs.md

@@ -51,13 +51,13 @@ Prefix: **LPI**
 
 ## Back-Face Normal Filter
 
-- [ ] **LPI-PROC-060**: When `filter-normal-facingness` ≥ -0.5, the system shall evaluate each incoming sensor hit against the back-face criterion before any other filtering: compute `facingness = dot(quatrotatevector(OutPose.Rot, sensor_normals[sensor_id]), normalize(bsd[lh].Pose.Pos - sensorInWorld))` and reject the hit if `facingness < filterNormalFacingness`.
-- [ ] **LPI-PROC-061**: When `filter-normal-facingness` < -0.5, the system shall skip the back-face filter entirely and pass the hit to subsequent filtering stages unchanged.
-- [ ] **LPI-PROC-062**: If the tracked object's `sensor_normals` or `sensor_locations` field is NULL, the system shall skip the back-face filter for that object (not all device types carry sensor geometry data).
-- [ ] **LPI-PROC-063**: While `poseConfidence` is below `filter-normal-min-confidence`, the system shall skip the back-face filter (pose not yet reliable enough to compute a trustworthy world-frame normal).
-- [ ] **LPI-PROC-064**: If the lighthouse referenced by the incoming hit does not yet have `PositionSet`, the system shall skip the back-face filter for that hit (lighthouse position needed to compute direction-to-LH).
-- [ ] **LPI-PROC-065**: The back-face filter shall run before the Chauvenet outlier filter so that geometrically impossible hits are rejected upstream, before they influence the per-sensor running statistics.
-- [ ] **LPI-PROC-066**: When `filter-normal-facingness` ≥ -0.5 and a hit is rejected by the back-face filter, the system shall emit a `SV_VERBOSE(105)` log line including the measured facingness, the threshold, and the (lh, sensor_id, axis) triple.
+- [x] **LPI-PROC-060**: When `filter-normal-facingness` ≥ -0.5, the system shall evaluate each incoming sensor hit against the back-face criterion before any other filtering: compute `facingness = dot(quatrotatevector(OutPose.Rot, sensor_normals[sensor_id]), normalize(bsd[lh].Pose.Pos - sensorInWorld))` and reject the hit if `facingness < filterNormalFacingness`.
+- [x] **LPI-PROC-061**: When `filter-normal-facingness` < -0.5, the system shall skip the back-face filter entirely and pass the hit to subsequent filtering stages unchanged.
+- [x] **LPI-PROC-062**: If the tracked object's `sensor_normals` or `sensor_locations` field is NULL, the system shall skip the back-face filter for that object (not all device types carry sensor geometry data).
+- [x] **LPI-PROC-063**: While `poseConfidence` is below `filter-normal-min-confidence`, the system shall skip the back-face filter (pose not yet reliable enough to compute a trustworthy world-frame normal).
+- [x] **LPI-PROC-064**: If the lighthouse referenced by the incoming hit does not yet have `PositionSet`, the system shall skip the back-face filter for that hit (lighthouse position needed to compute direction-to-LH).
+- [x] **LPI-PROC-065**: The back-face filter shall run before the Chauvenet outlier filter so that geometrically impossible hits are rejected upstream, before they influence the per-sensor running statistics.
+- [x] **LPI-PROC-066**: When `filter-normal-facingness` ≥ -0.5 and a hit is rejected by the back-face filter, the system shall emit a `SV_VERBOSE(105)` log line including the measured facingness, the threshold, and the (lh, sensor_id, axis) triple.
 
 ## Reprojection Model