Add Eloverblik data pipeline: fetch metering points, readings, and charges to PostgreSQL

- Add eloverblik controller with API client for metering points, time series, and charges
- Add migrations for metering_points, meter_readings, and charges tables
- Add HugSQL queries (upsert-metering-point!, insert-meter-reading!, insert-charge!)
- Add POST /eloverblik/sync route to trigger sync from browser

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

resources/migrations/20260214160000-create-charges.up.sql

@@ -0,0 +1,16 @@
+CREATE TABLE charges (
+  id                 SERIAL,
+  metering_point_id  VARCHAR(18) NOT NULL REFERENCES metering_points(metering_point_id),
+  charge_type        VARCHAR(20) NOT NULL,
+  name               VARCHAR(200) NOT NULL,
+  description        VARCHAR(500),
+  owner              VARCHAR(100) NOT NULL,
+  valid_from_date    DATE NOT NULL,
+  valid_to_date      DATE,
+  period_type        VARCHAR(50),
+  price              NUMERIC(12,6),
+  quantity           INTEGER,
+  position           INTEGER NOT NULL DEFAULT 0,
+  fetched_at         TIMESTAMPTZ NOT NULL DEFAULT now(),
+  UNIQUE (metering_point_id, charge_type, name, owner, valid_from_date, position)
+);