feat(story-1.2): add database migration system with golang-migrate

Makefile

@@ -1,4 +1,4 @@
-.PHONY: dev build run test lint clean docker-up docker-down migrate-up migrate-down
+.PHONY: dev build run test lint clean docker-up docker-down migrate-up migrate-down migrate-create
 
 # Development
 dev:
@@ -32,12 +32,25 @@ docker-down:
 docker-logs:
 	docker-compose logs -f
 
-# Database migrations (placeholder for Story 1.2)
+# Database migrations
+# Requires: go install -tags 'postgres' github.com/golang-migrate/migrate/v4/cmd/migrate@latest
+DB_URL ?= postgres://flowreader:flowreader@localhost:5432/flowreader?sslmode=disable
+
 migrate-up:
-	@echo "Migration system not yet configured (Story 1.2)"
+	migrate -path ./migrations -database "$(DB_URL)" up
 
 migrate-down:
-	@echo "Migration system not yet configured (Story 1.2)"
+	migrate -path ./migrations -database "$(DB_URL)" down 1
+
+migrate-drop:
+	migrate -path ./migrations -database "$(DB_URL)" drop -f
+
+migrate-create:
+	@read -p "Migration name: " name; \
+	migrate create -ext sql -dir ./migrations -seq $$name
+
+migrate-version:
+	migrate -path ./migrations -database "$(DB_URL)" version
 
 # Cleanup
 clean: