feat(go-crm): full auth, routing, middleware, and supporting infra

- Add auth handlers (signup, login, logout, account management) with bcrypt
- Add client, customer, service, scheduling, payment, question, answer handlers
- Add dashboard, monthly report, and lead pipeline pages
- Add UTF-8 middleware to force charset on HTML responses
- Add config package with env-based overrides for DB path, secrets, endpoints
- Add parser package for WhatsApp message ingestion
- Add clean-arch layers: pkg/domain, pkg/repo, pkg/usecase for leads
- Add cmd/migrate utility for DB migrations
- Add Makefile, README, run-tests.sh, and dev scripts
- Update docker-compose.yml with memory limits
- Update .air.toml to exclude DB files and stop on errors
- Update whatsapp-sync dependencies and add src/index.js entrypoint
- Add whatsme standalone WhatsApp reader app (source only)
- Untrack .opencode-sandbox/data/go-crm.db from git history
- Expand root .gitignore: ngrok, tmp dirs, sandbox DBs, compiled binaries

apps/go-crm/pkg/usecase/lead_service.go

@@ -0,0 +1,28 @@
+// Package usecase implements application business logic.
+package usecase
+
+import (
+	"context"
+
+	"go-crm/pkg/domain"
+)
+
+// LeadService coordinates lead-related business rules.
+type LeadService struct {
+	Repo domain.LeadRepository
+}
+
+// NewLeadService constructs a LeadService with the given repository.
+func NewLeadService(repo domain.LeadRepository) *LeadService {
+	return &LeadService{Repo: repo}
+}
+
+// ListAllLeads returns paginated leads for a client.
+func (s *LeadService) ListAllLeads(ctx context.Context, clientID int64, limit, offset int) ([]domain.Lead, error) {
+	return s.Repo.ListAll(ctx, clientID, limit, offset)
+}
+
+// UpdateLead applies updates to a lead.
+func (s *LeadService) UpdateLead(ctx context.Context, lead domain.Lead) error {
+	return s.Repo.Update(ctx, lead)
+}