feat: add tenant and user management with migrations, handlers, and tests

- Implemented tenant and user management features including:
  - Tenant creation and management with associated migrations.
  - User creation and management with associated migrations.
  - Tenant membership management with associated migrations.
  - Platform user roles management with associated migrations.
  - Quota management with associated migrations.
  - Article and template management with associated migrations.
- Added HTTP handlers for templates and workspaces.
- Created tests for protected and public routes.
- Introduced a script to check tenant scope in SQL queries.
- Documented task plan for backend completion and frontend foundation.

server/internal/shared/observability/logger.go

@@ -0,0 +1,23 @@
+package observability
+
+import (
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+func NewLogger(level, format string) (*zap.Logger, error) {
+	var cfg zap.Config
+	if format == "json" {
+		cfg = zap.NewProductionConfig()
+	} else {
+		cfg = zap.NewDevelopmentConfig()
+	}
+
+	lvl, err := zapcore.ParseLevel(level)
+	if err != nil {
+		lvl = zapcore.InfoLevel
+	}
+	cfg.Level = zap.NewAtomicLevelAt(lvl)
+
+	return cfg.Build()
+}