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/20260214140000-create-metering-points.down.sql

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+DROP TABLE IF EXISTS metering_points;

resources/migrations/20260214140000-create-metering-points.up.sql

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+CREATE TABLE metering_points (
+  metering_point_id  VARCHAR(18)  PRIMARY KEY,
+  type_of_mp         VARCHAR(50),
+  balance_supplier   VARCHAR(100),
+  street_name        VARCHAR(200),
+  building_number    VARCHAR(20),
+  postcode           VARCHAR(10),
+  city_name          VARCHAR(100),
+  has_relation       BOOLEAN,
+  settlement_method  VARCHAR(50),
+  reading_occurrence VARCHAR(50),
+  consumer_start_date DATE,
+  first_consumer_name VARCHAR(200),
+  fetched_at         TIMESTAMPTZ NOT NULL DEFAULT now()
+);

resources/migrations/20260214150000-create-meter-readings.down.sql

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+DROP TABLE IF EXISTS meter_readings;

resources/migrations/20260214150000-create-meter-readings.up.sql

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+CREATE TABLE meter_readings (
+  metering_point_id  VARCHAR(18) NOT NULL REFERENCES metering_points(metering_point_id),
+  time_dk            TIMESTAMP   NOT NULL,
+  quantity_kwh       NUMERIC(10,3),
+  quality            VARCHAR(50),
+  PRIMARY KEY (metering_point_id, time_dk)
+);
+--;;
+CREATE INDEX idx_meter_readings_time_dk ON meter_readings(time_dk);

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

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+DROP TABLE IF EXISTS charges;

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

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+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)
+);