Phase 0: record host bring-up progress on the car unit

LTE is up over QMI on povo, metered and ranked below Ethernet/WiFi, with
failover tested. CAN interfaces now have stable udev names (can_pcan,
can_onboard) since canN order raced at boot, so references to can1/can0
go. GNSS stays open: gpsd runs but has no fix until an open-sky test,
which is now what blocks the moving map. Kernel-update rebuild steps
are documented for both out-of-tree modules; time sync is pinned to NICT.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/ROADMAP.md

@@ -1,7 +1,7 @@
 ---
 type: plan
 status: active
-updated: 2026-09-04
+updated: 2026-10-08
 ---
 # Roadmap
 
@@ -12,11 +12,19 @@ something demonstrable in the car.
 
 Getting the Jetson to see the hardware at all.
 
-- [x] PCAN-USB working as SocketCAN `can1` (out-of-tree `pcan.ko`, netdev build)
+- [x] PCAN-USB working as SocketCAN (out-of-tree `pcan.ko`, netdev build)
+- [x] Stable CAN names by udev: `can_pcan`, `can_onboard` — `canN` order raced at boot
 - [x] SIM7600G-H-M.2 specified and documented
-- [ ] SIM7600 brought up: LTE data path and GNSS via gpsd
-- [ ] Kernel-update procedure for the out-of-tree PCAN module — it does not
-      survive kernel upgrades and will break silently
+- [x] SIM7600 LTE data path: QMI (self-built `qmi_wwan`), povo, metered, ranked
+      below Ethernet/WiFi; failover tested, Tailscale stays reachable over LTE
+- [ ] SIM7600 GNSS via gpsd — pipeline up (`/dev/sim7600-gps`), **no fix yet**;
+      needs an open-sky test
+- [x] Kernel-update procedure for the out-of-tree modules (`pcan`, `qmi_wwan`) —
+      documented, sources kept in `~/infra`; still manual, and breaks silently
+      if forgotten
+- [x] Network time pinned to NICT; timezone `Asia/Tokyo`
+- [ ] Optional: RTC backup battery (CR2032) — without it the clock boots stale
+      until NTP or GPS corrects it
 - [ ] Power and mounting in the car: clean shutdown on ignition off
 
 Tracked in [orin-nano-env-setup](gitea:yukart/orin-nano-env-setup).
@@ -79,7 +87,7 @@ and `tool-mapmint` (artifact builds).
 - [ ] Pull a Japan basemap extract from the Protomaps daily build with
       `go-pmtiles`; static-serve it, with `localIdeographFontFamily` set for CJK
 - [ ] MapLibre page rendering the basemap from a replayed GNSS trace
-- [ ] Moving map live in the car — **blocked on gpsd in Phase 0**
+- [ ] Moving map live in the car — **blocked on a GNSS fix in Phase 0**
 - [ ] Meili map matching over recorded sessions, as Phase 2 ground truth
 - [ ] Routing and turn-by-turn guidance onto `yukart/nav/guidance`