Server: InfluxDB 2 storage, live telemetry endpoint, ABRP forwarder

- MongoDB replaced by InfluxDB 2 (one bucket, installationId tag).
  Consumption is stored per chunk at its recordedAt and summed on read,
  so a chunk the car re-sends from its cache overwrites itself instead
  of being counted twice ($inc did count it twice). Lifetime is a
  running total derived on read.
- POST /v1/telemetry takes batches of samples in ABRP's tlm fields; every
  field is bounded, unknown fields are dropped, unread signals stay absent.
- After a successful write the newest fresh sample is forwarded to ABRP
  with ABRP_API_KEY / ABRP_USER_TOKEN from the server environment; rate
  limited, never queued. The car no longer needs ABRP credentials.
- Self-hosting: standalone output, Dockerfile (tests run in the build,
  runs as UID 10001), .env.example and README for the new setup.
- Dev shell gains Node 22 and InfluxDB 2.

Verified locally against InfluxDB 2.7.12: all endpoints, retry
idempotency, and the dashboard pages. Unit tests: 17 pass.

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

web/.env.example

@@ -1,5 +1,18 @@
-MONGODB_URI=mongodb+srv://username:password@cluster.example.mongodb.net/
-MONGODB_DATABASE=fatihsmg4
+# InfluxDB 2 — a token with read/write on the bucket.
+INFLUX_URL=http://influxdb:8086
+INFLUX_TOKEN=replace-with-an-influxdb-token
+INFLUX_ORG=mg4
+INFLUX_BUCKET=mg4
+
+# The car's write token (at least 24 characters): openssl rand -hex 32
 INGEST_TOKEN=replace-with-a-long-random-write-token
+# Signs dashboard sessions; rotating it signs every browser out: openssl rand -hex 32
 SESSION_SECRET=replace-with-a-long-random-session-secret
+# Dashboard login, at least 8 characters.
 DASHBOARD_PASSWORD=replace-with-a-strong-dashboard-password
+
+# ABRP forwarding; off when either is empty.
+ABRP_API_KEY=
+ABRP_USER_TOKEN=
+# Minimum seconds between two samples forwarded to ABRP.
+ABRP_MIN_INTERVAL_SECONDS=5