Reorganize repo: backend/, deploy/, docs/ layout + AGENTS.md

Restructure the monorepo into clear top-level directories:
- backend/: Go module root (cmd, internal, pkg, configs, migrations,
  docs/swagger, scripts, tests, go.mod, Makefile, .air.toml)
- deploy/: Docker (Dockerfile, docker-compose*), quickstart, fluentd
- docs/: project documentation + reports/ (moved from repo root)
- AGENTS.md: new AI coding-agent guide at repo root

Update all references to the new layout:
- Dockerfile: COPY backend/go.mod, COPY backend/ (context = repo root)
- docker-compose files: context ../.., dockerfile deploy/docker/Dockerfile,
  env_file ../../.env, volume mounts ../../backend:/app
- deploy/quickstart/compose.yaml: dockerfile deploy/docker/Dockerfile
- CI: working-directory: backend for go commands, file deploy/docker/Dockerfile,
  coverage path backend/coverage.out, health_check backend/scripts/
- backend/Makefile: docker target uses -f ../deploy/docker/Dockerfile ../
- README: architecture tree, quickstart, config paths updated

Move root stray scripts (rename_models.*, run_m11_tests.sh, verify_build.sh,
gorm_bool_main.go) to backend/scripts/legacy/. All moves via git mv to
preserve history. Build, vet, SQLite tests, and docker compose config verified.

backend/internal/reporting/service.go

@@ -0,0 +1,83 @@
+package reporting
+
+import (
+	"context"
+	"time"
+
+	"gorm.io/gorm"
+)
+
+// ReportingService provides CRUD and aggregation queries for reporting events and rollups.
+// Reference: Chatwoot Reports::ReportingEventService + Reports::ReportingEventsRollupService
+type ReportingService struct {
+	db *gorm.DB
+}
+
+func NewReportingService(db *gorm.DB) *ReportingService {
+	return &ReportingService{db: db}
+}
+
+// CreateEvent records a new reporting event.
+func (s *ReportingService) CreateEvent(ctx context.Context, event *ReportingEvent) error {
+	return s.db.WithContext(ctx).Create(event).Error
+}
+
+// GetEvent retrieves a single reporting event by ID.
+func (s *ReportingService) GetEvent(ctx context.Context, id uint) (*ReportingEvent, error) {
+	var event ReportingEvent
+	if err := s.db.WithContext(ctx).First(&event, id).Error; err != nil {
+		return nil, err
+	}
+	return &event, nil
+}
+
+// ListEventsByAccount returns all reporting events for an account within a time range.
+func (s *ReportingService) ListEventsByAccount(ctx context.Context, accountID uint, since, until time.Time) ([]ReportingEvent, error) {
+	var events []ReportingEvent
+	err := s.db.WithContext(ctx).Where("account_id = ? AND event_start_time >= ? AND event_start_time <= ?", accountID, since, until).
+		Find(&events).Error
+	return events, err
+}
+
+// ListEventsByAccountAndName returns events filtered by account, metric name, and time range.
+func (s *ReportingService) ListEventsByAccountAndName(ctx context.Context, accountID uint, name string, since, until time.Time) ([]ReportingEvent, error) {
+	var events []ReportingEvent
+	err := s.db.WithContext(ctx).Where("account_id = ? AND name = ? AND event_start_time >= ? AND event_start_time <= ?", accountID, name, since, until).
+		Find(&events).Error
+	return events, err
+}
+
+// CreateRollup records a rollup aggregation row. Uses upsert to handle the unique index constraint.
+func (s *ReportingService) CreateRollup(ctx context.Context, rollup *ReportingEventsRollup) error {
+	return s.db.WithContext(ctx).Where("account_id = ? AND date = ? AND dimension_type = ? AND dimension_id = ? AND metric = ?",
+		rollup.AccountID, rollup.Date, rollup.DimensionType, rollup.DimensionID, rollup.Metric).
+		Assign(map[string]interface{}{
+			"count":                    rollup.Count,
+			"sum_value":                rollup.SumValue,
+			"sum_value_business_hours": rollup.SumValueBusinessHours,
+		}).FirstOrCreate(rollup).Error
+}
+
+// GetRollups returns rollup records for an account within a date range.
+func (s *ReportingService) GetRollups(ctx context.Context, accountID uint, dimensionType DimensionType, dimensionID uint, since, until time.Time) ([]ReportingEventsRollup, error) {
+	var rollups []ReportingEventsRollup
+	err := s.db.WithContext(ctx).Where("account_id = ? AND dimension_type = ? AND dimension_id = ? AND date >= ? AND date <= ?",
+		accountID, dimensionType, dimensionID, since, until).
+		Find(&rollups).Error
+	return rollups, err
+}
+
+// GetRollupsByMetric returns rollup records for a specific metric.
+func (s *ReportingService) GetRollupsByMetric(ctx context.Context, accountID uint, dimensionType DimensionType, dimensionID uint, metric RollupMetric, since, until time.Time) ([]ReportingEventsRollup, error) {
+	var rollups []ReportingEventsRollup
+	err := s.db.WithContext(ctx).Where("account_id = ? AND dimension_type = ? AND dimension_id = ? AND metric = ? AND date >= ? AND date <= ?",
+		accountID, dimensionType, dimensionID, metric, since, until).
+		Find(&rollups).Error
+	return rollups, err
+}
+
+// DeleteRollupsByDate removes rollup records for a given date range (for re-computation).
+func (s *ReportingService) DeleteRollupsByDate(ctx context.Context, accountID uint, since, until time.Time) error {
+	return s.db.WithContext(ctx).Where("account_id = ? AND date >= ? AND date <= ?", accountID, since, until).
+		Delete(&ReportingEventsRollup{}).Error
+}