Fix slow OBD value load on dashboard (BUG-19)

BUGS.md

@@ -37,6 +37,22 @@ When CLOSED, move the entire entry to Resolved — don't duplicate.
   - Keep `systemd-timesyncd` for online NTP; fall back to the RTC (DS3231) and optionally
     GNSS time when offline.
 
+### BUG-19 — Dashboard OBD values slow to appear while the car is running
+- **Status**: `OPEN` 2026-08-13
+- **Phase**: 29
+- **Symptom**: on the Pi dashboard, the speed/RPM/coolant/fuel/throttle cards stay on
+  "—" for a long time after the page loads (or after ignition) before populating, even
+  though the car is running and OBD is connected.
+- **Cause**: the value cards were populated **only** by socket.io push events from the
+  OBD polling threads — the dashboard never pulled a current snapshot on load, so a
+  freshly loaded page had to wait for the next poll tick (plus any reconnect/probe
+  latency). `/api/obd/status` only returned the connection state, not the actual
+  values, so there was no REST fallback either.
+- **Fix**: emit a full current-value snapshot on socket connect, and extend
+  `/api/obd/status` to return live speed/RPM/coolant/fuel/throttle/MIL so the dashboard
+  fills the cards immediately on load (and every 15 s) via REST. Needs in-car
+  verification.
+
 ---
 
 ## Resolved