docs: close BUG-15 — phone-OS limitation (dual-role), workaround documented

BUGS.md

@@ -8,21 +8,6 @@ When CLOSED, move the entire entry to Resolved — don't duplicate.
 
 ## Open bugs
 
-### BUG-15 — Phone can't host the hotspot and connect to the Pi's AP at once
-- **Status**: `OPEN` 2026-08-12
-- **Symptom**: With the phone hosting the hotspot (Pi's uplink) *and* connected to the
-  Pi's AP ("vroom vroom yaris de course"), the Pi loses internet. Uploads fail with
-  `NameResolutionError` — the phone's WiFi-sharing routes the hotspot's traffic back
-  through the no-internet AP, creating a routing loop.
-- **Cause**: phone-OS limitation — a single phone can't cleanly be both the Pi's
-  internet uplink (AP/hotspot host) and its WiFi client (on the Pi's AP) simultaneously.
-- **Intended use / workaround**: phone must be **LTE-only** (WiFi off) to serve as the
-  Pi's uplink. Reach the Pi UI from that phone over the hotspot at
-  `http://<pi-hotspot-ip>` (Settings → "In-car hotspot" shows it), or from a second
-  device on the AP.
-- **Pi-side hardening shipped 2026-08-12**: `phone-hotspot` now forces public DNS
-  (`8.8.8.8`/`1.1.1.1`) and the Settings page surfaces the correct URL per uplink mode.
-
 ### BUG-17 — Server trip timestamps wrong after an offline period
 - **Status**: `OPEN` 2026-08-13
 - **Phase**: 29
@@ -56,6 +41,19 @@ When CLOSED, move the entire entry to Resolved — don't duplicate.
 
 ## Resolved
 
+### BUG-15 — Phone can't host the hotspot and connect to the Pi's AP at once
+- **Status**: `CLOSED` 2026-08-13
+- **Commit**: `cc06c62`
+- **Resolution**: Confirmed a **phone-OS limitation**, not a Pi bug. A single phone
+  can't cleanly be both the Pi's internet uplink (hotspot/AP host) and its WiFi client
+  (on the Pi's AP) at the same time — doing so routes the hotspot's traffic back through
+  the no-internet AP, creating a routing loop (`NameResolutionError` on uploads).
+- **Workaround (documented)**: the phone must be **LTE-only** (WiFi off) to serve as the
+  Pi's uplink. Reach the Pi UI from that phone over the hotspot at
+  `http://<pi-hotspot-ip>` (Settings → "In-car hotspot"), or from a second device on the AP.
+- **Pi-side hardening shipped**: `phone-hotspot` profile forces public DNS
+  (`8.8.8.8`/`1.1.1.1`), and the Settings page surfaces the correct URL per uplink mode.
+
 ### BUG-16 — Trip missing from Pi local history (present on server)
 - **Status**: `CLOSED` 2026-08-13
 - **Commits**: `e5ac14e`, `f5f20c3`