Update .gitignore to include .env and .DS_Store files

Add .cursor autodevelopment system

.cursor/rules/openapi.mdc

@@ -0,0 +1,15 @@
+---
+description: "OpenAPI/Swagger API documentation standards — applied when editing API spec files"
+globs: ["**/openapi*", "**/swagger*"]
+alwaysApply: false
+---
+# OpenAPI
+
+- Use OpenAPI 3.0+ specification
+- Define reusable schemas in `components/schemas`; reference with `$ref`
+- Include `description` for every endpoint, parameter, and schema property
+- Define `responses` for at least 200, 400, 401, 404, 500
+- Use `tags` to group endpoints by domain
+- Include `examples` for request/response bodies
+- Version the API in the path (`/api/v1/`) or via header
+- Use `operationId` for code generation compatibility