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/Makefile

@@ -0,0 +1,41 @@
+.PHONY: dev-init dev-api migrate-up migrate-down migrate-create sqlc-generate tenant-scope-guard lint test tidy seed
+
+DB_URL ?= postgres://geo:geo_dev@localhost:5432/geo?sslmode=disable
+MIGRATE_CMD ?= go run -tags postgres github.com/golang-migrate/migrate/v4/cmd/migrate@v4.19.1
+
+dev-init: ## Start infra, run migrations, seed data
+	docker compose up -d
+	@echo "Waiting for postgres..."
+	@sleep 3
+	$(MAKE) migrate-up
+	$(MAKE) seed
+
+dev-api: ## Run tenant-api server
+	go run ./cmd/tenant-api
+
+migrate-up: ## Run all pending migrations
+	$(MIGRATE_CMD) -path migrations -database "$(DB_URL)" up
+
+migrate-down: ## Rollback last migration
+	$(MIGRATE_CMD) -path migrations -database "$(DB_URL)" down 1
+
+migrate-create: ## Create new migration (usage: make migrate-create NAME=xxx)
+	$(MIGRATE_CMD) create -ext sql -dir migrations -seq $(NAME)
+
+sqlc-generate: ## Generate typed Go code from SQL queries
+	cd internal/tenant/repository && sqlc generate
+
+tenant-scope-guard: ## Ensure tenant-scoped SQL includes tenant_id filters
+	bash scripts/check_tenant_scope.sh
+
+seed: ## Insert development seed data
+	go run ./cmd/dev-seed
+
+lint: ## Run linter
+	golangci-lint run ./...
+
+test: ## Run all tests
+	go test ./... -count=1
+
+tidy: ## Tidy go modules
+	go mod tidy