P0: live provider chain — GitHub mirror primary, relay fallback, bundled dump last resort + app telemetry beacon

- MirrorFuelProvider: fetches CURRENT prices from raw.githubusercontent
  (latest.json pointer → history/<day>.json full dump), app-group day-cache
  so the ~2.8 MB dump is re-downloaded only when the mirror pushes a new day
- LiveChainProvider: full path (app refresh) GitHub → relay; focused path
  (background alert checks) relay-first so alerts never pull the full dump
  over mobile data; records which leg served for About + telemetry
- FuelBeacon: fire-and-forget X-Client app ping to the relay's existing
  widget-diag route (zero relay changes) — attribution + cadence on-LAN,
  silent skip off-LAN is the reachability datum; /stats app-hit spike =
  GitHub path failing
- Bundled dump: FuelBoardDump dataset (real 2026-08-15 snapshot, 8,022
  stations) + BundledDumpProvider + scripts/refresh_bundled_dump.sh —
  no-network last resort replaces the demo sample set
- ContentView: About meta from the chain; catch falls back cached → bundled
  → sample
- 89 tests (6 new: chain order x4, cache decision, beacon URL); Release
  build green; beacon route verified against the live relay (204 + logged)

scripts/refresh_bundled_dump.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+# Refresh the bundled fallback dump (FuelBoardDump dataset) from the GitHub
+# mirror — run before a Release build so the IPA carries the freshest REAL
+# snapshot (the app's no-network last resort). Idempotent: skips when the
+# bundled dump already carries the mirror's data_updated stamp.
+set -euo pipefail
+cd "$(dirname "$0")/.."
+TARGET="FuelBoard/Assets.xcassets/FuelBoardDump.dataset/fuelboard_dump.json"
+RAW="https://raw.githubusercontent.com/aptonline/fuelboard-data/main"
+LATEST="$(curl -fsSL "$RAW/latest.json")"
+DAY="$(printf '%s' "$LATEST" | python3 -c 'import json,sys; d=json.load(sys.stdin); print(d.get("available_to") or d.get("date") or "")')"
+UPD="$(printf '%s' "$LATEST" | python3 -c 'import json,sys; d=json.load(sys.stdin); print(d.get("data_updated") or "")')"
+if [ -z "$DAY" ]; then echo "no snapshot day in latest.json" >&2; exit 1; fi
+if [ -f "$TARGET" ] && grep -q "\"data_updated\": \"$UPD\"" "$TARGET"; then
+    echo "bundled dump already current ($DAY, $UPD)"
+    exit 0
+fi
+echo "fetching history/$DAY.json ($UPD)…"
+curl -fsSL "$RAW/history/$DAY.json" -o "$TARGET"
+echo "updated $TARGET — $DAY"