Replace the Express service with a Next.js app on Vercel

The standalone service in server/ was never deployed anywhere, and keeping it
alongside a Vercel app would mean maintaining two implementations of the same
validation rules. It is deleted; web/ is the only ingest path now. Its routes
live at /v1/... rather than under /api, so the Android client's URL building is
unchanged and CONSUMPTION_API_URL stays a bare origin.

Credentials are split in two. INGEST_TOKEN is baked into the published APK and
must be assumed extractable — anyone can unzip an APK and read its strings — so
it opens the PUT endpoints and nothing else. Reading the history needs the
dashboard password, which is never compiled into anything and reaches the
browser as an HMAC-signed httpOnly cookie. The MongoDB URI stays a server-side
environment variable; the car has never held one and still does not.

The dashboard is a phone-shaped reader for the same data: totals for energy
taken and paid, a daily energy chart, an efficiency trend, and every DC session
with its power/SOC curve. It reuses the head unit's OLED palette so the two read
as one app. Every page is a server component and the charts are hand-rolled SVG,
so the whole thing renders without shipping client JavaScript.

MongoClient is cached on globalThis: a fresh client per request means a fresh
pool per request, and Atlas starts refusing connections long before the traffic
would justify it. Index creation moved to the first write of each warm lambda,
since a serverless deployment has no boot step to hang it on.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

server/README.md

@@ -1,27 +0,0 @@
-# FatihsMG4 consumption API
-
-The Android app never connects to MongoDB directly and never contains a MongoDB URI. This
-service stores completed daily totals in `daily_consumption` and each completed charge,
-including its SOC/power curve and price, in `charging_sessions`.
-
-## Run
-
-1. Copy `.env.example` to `.env` and fill in the MongoDB Atlas URI and a random API token.
-2. Export the variables (Node does not load `.env` automatically), then run `npm install` and
-   `npm start`.
-3. Build the Android app with the public HTTPS service address and the same token:
-
-   ```sh
-   CONSUMPTION_API_URL=https://your-api.example.com \
-   CONSUMPTION_API_TOKEN=your-random-token \
-   ./gradlew assembleUnstableRelease
-   ```
-
-If either Android build variable is missing, cloud sync is disabled and local consumption
-tracking continues unchanged. The car retries locally queued charging sessions every five minutes.
-Daily consumption is uploaded once after the day closes; missed days are retried in order.
-
-The future mobile client can read authenticated history from:
-
-- `GET /v1/consumption/:installationId`
-- `GET /v1/charging-sessions/:installationId`