docs: BUG-12 closed — OBD API fallback fixes dashboard blank state, GPS toFixed crash fixed

BUGS.md

@@ -44,6 +44,21 @@ When CLOSED, move the entire entry to Resolved — don't duplicate.
 
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+### BUG-12 — Dashboard OBD shows "—" while Status page shows correct OBD state
+- **Status**: `CLOSED` 2026-08-11
+- **Commit**: `91281b1`
+- **Symptom**: Dashboard OBD card showed "—" (blank) even though the Status
+  page correctly reported adapter present at /dev/ttyUSB0 (disconnected from car).
+- **Root cause**: Dashboard relied solely on Socket.IO `obd_status` events. If
+  the page loaded after the initial event fired, the card stayed at the HTML
+  default. Status page queried `_obd_status()` directly.
+- **Fix**: Added `/api/obd/status` endpoint. Dashboard calls `refreshObdStatus()`
+  on load + every 15s. Socket events still update in real-time.
+- **Side fix**: `renderGpsStatus()` crashed on `status.latitude.toFixed` because
+  the API returns lat/lon as strings — fixed with `Number()` wrapper.
+- **Verification**: Dashboard shows "Disconnected" matching Status page. GPS no
+  longer crashes. Confirmed on live Pi 2026-08-11.
+
 ---
 
 ## Resolved