fix(#505,#506): bump firmware to v0.6.4 + no-signal UI indicator

Fixes #505 — version string mismatch:
- firmware/esp32-csi-node/version.txt: 0.6.2 → 0.6.4
- .github/workflows/firmware-ci.yml: add verify-embedded-version step
  that extracts the esp_app_desc version string from the built binary and
  fails CI if it doesn't match version.txt. Prevents the v0.6.3 regression
  (tagged without bumping version.txt) from recurring.

Fixes #506 — stale skeleton shown after ESP32 unplugged:
- csi_pipeline.rs: add CsiPipelineState::last_csi_received (Instant),
  stamped on every process_frame() call; PipelineOutput gains csi_live:bool
  (true iff a real frame arrived within the last 5 s).
- stream.rs: /api/splats now includes csi_live in the JSON response.
- viewer.html: add #no-signal banner (red, centered overlay) shown when
  the server reports csi_live=false in live/remote transport mode.
  Skeleton is cleared while the banner is visible so stale pose data
  is not presented as live activity.

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

.github/workflows/firmware-ci.yml

@@ -98,6 +98,32 @@ jobs:
             echo "Flash image integrity verified"
           fi
 
+      - name: Verify embedded version string matches version.txt (fixes #505)
+        working-directory: firmware/esp32-csi-node
+        run: |
+          EXPECTED=$(cat version.txt | tr -d '[:space:]')
+          BIN=build/esp32-csi-node.bin
+          # Extract version from ESP-IDF app_desc: magic 0xABCD5432 at offset 0
+          # followed by version string at offset 16, null-terminated, max 32 chars.
+          EMBEDDED=$(python3 -c "
+import struct, sys
+data = open('$BIN','rb').read()
+magic = struct.pack('<I', 0xABCD5432)
+i = data.find(magic)
+if i < 0:
+    sys.exit('app_desc magic not found')
+ver = data[i+16:i+48].split(b'\\x00',1)[0].decode('ascii','replace')
+print(ver)
+" 2>&1)
+          echo "Expected version: $EXPECTED"
+          echo "Embedded version: $EMBEDDED"
+          if [ "$EMBEDDED" != "$EXPECTED" ]; then
+            echo "::error::Version string mismatch! version.txt='$EXPECTED' but binary reports '$EMBEDDED'."
+            echo "::error::Ensure version.txt is updated before building and tagging."
+            exit 1
+          fi
+          echo "Version string verified: $EMBEDDED"
+
       - name: Stage release binaries with variant-specific names
         working-directory: firmware/esp32-csi-node
         run: |

firmware/esp32-csi-node/version.txt

@@ -1 +1 @@
-0.6.2
+0.6.4

v2/crates/wifi-densepose-pointcloud/src/csi_pipeline.rs

@@ -65,6 +65,9 @@ pub struct CsiPipelineState {
     pub current_location: Option<(String, f32)>,
     /// Night mode — true when camera luminance is below threshold
     pub is_dark: bool,
+    /// Wall-clock instant the last real ESP32 UDP CSI frame was received.
+    /// `None` if no frame has arrived since startup.
+    pub last_csi_received: Option<std::time::Instant>,
     /// Metadata from the on-disk WiFlow JSON, if one is present. NOTE: the
     /// weights themselves are NOT loaded or executed in this crate — this
     /// flag merely enables the amplitude-energy heuristic pose code path.
@@ -91,6 +94,7 @@ impl Default for CsiPipelineState {
             fingerprints: Vec::new(),
             current_location: None,
             is_dark: false,
+            last_csi_received: None,
             pose_model_present: detect_pose_model_metadata(),
         }
     }
@@ -133,6 +137,7 @@ impl CsiPipelineState {
     pub fn process_frame(&mut self, frame: CsiFrame) {
         let node_id = frame.node_id;
         self.total_frames += 1;
+        self.last_csi_received = Some(std::time::Instant::now());
 
         // Once every 500 frames log a one-line node stats summary. This keeps
         // us honest about the CSI shape we are actually receiving and also
@@ -584,6 +589,9 @@ pub fn get_pipeline_output(state: &Arc<Mutex<CsiPipelineState>>) -> PipelineOutp
         num_nodes: st.node_frames.len(),
         current_location: st.current_location.clone(),
         is_dark: st.is_dark,
+        csi_live: st.last_csi_received
+            .map(|t| t.elapsed() < std::time::Duration::from_secs(5))
+            .unwrap_or(false),
     }
 }
 
@@ -598,6 +606,10 @@ pub struct PipelineOutput {
     pub num_nodes: usize,
     pub current_location: Option<(String, f32)>,
     pub is_dark: bool,
+    /// True when a real ESP32 CSI frame was received in the last 5 seconds.
+    /// False means the pipeline is running on stale data — show a NO SIGNAL
+    /// indicator in the UI rather than presenting stale skeletons as live.
+    pub csi_live: bool,
 }
 
 // Serialize implementations

v2/crates/wifi-densepose-pointcloud/src/stream.rs

@@ -219,10 +219,12 @@ async fn api_splats(State(state): State<Arc<AppState>>) -> Json<serde_json::Valu
     let splats = state.latest_splats.lock().unwrap();
     let frames = *state.frame_count.lock().unwrap();
     let pipeline = state.latest_pipeline.lock().unwrap();
+    let csi_live = pipeline.as_ref().map(|p| p.csi_live).unwrap_or(false);
     Json(serde_json::json!({
         "splats": &*splats,
         "count": splats.len(),
         "live": state.use_camera,
+        "csi_live": csi_live,
         "frame": frames,
         "pipeline": &*pipeline,
         "timestamp": chrono::Utc::now().timestamp_millis(),

v2/crates/wifi-densepose-pointcloud/src/viewer.html

@@ -21,6 +21,17 @@
         .face { color: #4cf; }
         .section { margin-top: 6px; padding-top: 6px; border-top: 1px solid #333; }
         .label { color: #888; }
+        #no-signal {
+            display: none;
+            position: absolute; top: 50%; left: 50%;
+            transform: translate(-50%, -50%);
+            background: rgba(160,0,0,0.93); color: #fff;
+            font-family: monospace; font-size: 18px; font-weight: bold;
+            padding: 18px 32px; border-radius: 8px;
+            border: 2px solid #f44; text-align: center;
+            pointer-events: none; z-index: 20;
+        }
+        #no-signal .sub { font-size: 12px; font-weight: normal; margin-top: 6px; color: #fbb; }
     </style>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
     <script src="https://cdn.jsdelivr.net/npm/three@0.128.0/examples/js/controls/OrbitControls.js"></script>
@@ -29,6 +40,10 @@
     <script src="https://cdn.jsdelivr.net/npm/@mediapipe/camera_utils@0.3/camera_utils.js"></script>
 </head>
 <body>
+    <div id="no-signal">
+        &#x25CF; NO CSI SIGNAL
+        <div class="sub">No ESP32 frames received for &gt;5s.<br>Check that your node is powered and provisioned.</div>
+    </div>
     <div id="info">
         <h3 style="margin:0 0 4px 0">RuView · Seldon Vault</h3>
         <div style="font-size: 11px; color: #888; margin-bottom: 8px; max-width: 240px; line-height: 1.4; font-style: italic;">"Psychohistory deals with reactions of human conglomerates to fixed social and economic stimuli." — Hari Seldon</div>
@@ -56,6 +71,11 @@
         var skeletonGroup = null;
         var prevTimestamp = 0;
         var frameRateVal = 0;
+        // No-signal detection: track server-reported csi_live flag
+        var noSignalBanner = document.getElementById("no-signal");
+        function setNoSignal(isNoSignal) {
+            noSignalBanner.style.display = isNoSignal ? "block" : "none";
+        }
 
         // COCO skeleton connections: pairs of keypoint indices
         // 0=nose 1=leftEye 2=rightEye 3=leftEar 4=rightEar
@@ -579,9 +599,18 @@
                     data._faceOverlay = faceOverlay;
                     updateSplats(rendered);
 
-                    // Draw skeleton if available
+                    // No-signal detection: hide skeleton and show banner when
+                    // the server reports no live CSI frames in the last 5s.
                     var pipe = data.pipeline;
-                    if (pipe && pipe.skeleton && pipe.skeleton.keypoints) {
+                    var csiLive = data.csi_live || (pipe && pipe.csi_live);
+                    // Only show no-signal when connected to a real backend
+                    // (not demo/face-mesh mode where csi_live is always false).
+                    var showNoSignal = (transportMode === "live" || transportMode === "remote")
+                        && csiLive === false;
+                    setNoSignal(showNoSignal);
+                    if (showNoSignal) {
+                        clearSkeleton();
+                    } else if (pipe && pipe.skeleton && pipe.skeleton.keypoints) {
                         drawSkeleton(pipe.skeleton.keypoints);
                     } else {
                         clearSkeleton();