Implement ingest-service: MQTT -> ClickHouse (batched) + RabbitMQ event

Subscribes to devices/+/telemetry, validates payloads, buffers writes into
ClickHouse (flush on size or interval), and emits a per-reading event on
RabbitMQ for rule-engine-service to consume later. Adds the initial Postgres
and ClickHouse schema migrations, a Dockerfile, and wires the service into
docker-compose. Verified end-to-end via docker compose + mosquitto_pub: row
lands in ClickHouse and the event reaches the telemetry.new_reading queue.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

services/ingest-service/internal/clickhouse/store.go

@@ -0,0 +1,76 @@
+// Package clickhouse writes batches of telemetry readings to ClickHouse.
+package clickhouse
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+
+	ch "github.com/ClickHouse/clickhouse-go/v2"
+	"github.com/ClickHouse/clickhouse-go/v2/lib/driver"
+
+	"git.cactoz.su/cacto/home_automatization/services/ingest-service/internal/telemetry"
+)
+
+type Config struct {
+	Addr     string
+	Database string
+	Username string
+	Password string
+	UseTLS   bool
+}
+
+type Store struct {
+	conn driver.Conn
+}
+
+func Connect(ctx context.Context, cfg Config) (*Store, error) {
+	opts := &ch.Options{
+		Addr: []string{cfg.Addr},
+		Auth: ch.Auth{
+			Database: cfg.Database,
+			Username: cfg.Username,
+			Password: cfg.Password,
+		},
+	}
+	if cfg.UseTLS {
+		opts.TLS = &tls.Config{}
+	}
+
+	conn, err := ch.Open(opts)
+	if err != nil {
+		return nil, fmt.Errorf("open clickhouse connection: %w", err)
+	}
+	if err := conn.Ping(ctx); err != nil {
+		return nil, fmt.Errorf("ping clickhouse: %w", err)
+	}
+	return &Store{conn: conn}, nil
+}
+
+func (s *Store) Close() error {
+	return s.conn.Close()
+}
+
+// InsertBatch writes readings to the telemetry table in a single INSERT.
+func (s *Store) InsertBatch(ctx context.Context, readings []telemetry.Reading) error {
+	if len(readings) == 0 {
+		return nil
+	}
+
+	batch, err := s.conn.PrepareBatch(ctx, "INSERT INTO telemetry (device_id, zone_id, sensor_type, value, recorded_at, received_at)")
+	if err != nil {
+		return fmt.Errorf("prepare batch: %w", err)
+	}
+	defer batch.Close()
+
+	for _, r := range readings {
+		if err := batch.Append(r.DeviceID, r.ZoneID, r.SensorType, r.Value, r.RecordedAt, r.ReceivedAt); err != nil {
+			return fmt.Errorf("append reading for device %s: %w", r.DeviceID, err)
+		}
+	}
+
+	if err := batch.Send(); err != nil {
+		return fmt.Errorf("send batch: %w", err)
+	}
+	return nil
+}