Update project configuration and documentation

- Modified .gitignore to retain rules directory while excluding other cursor files.
- Updated backend-go.mdc to clarify compatibility notes.
- Enhanced project-conventions.mdc with guidelines on coding practices and running tests.
- Added SKILL.md for detailed instructions on running backend and frontend tests in the hnh-map monorepo.

.cursor/rules/project-conventions.mdc

@@ -10,3 +10,5 @@ alwaysApply: true
 - **Changing config:** Update [.env.example](.env.example) and [docs/configuration.md](docs/configuration.md).
 - **Local run / build:** [docs/development.md](docs/development.md), [CONTRIBUTING.md](CONTRIBUTING.md). Dev ports: frontend 3000, backend 3080; prod: 8080.
 - **Docs:** [docs/](docs/) (architecture, API, configuration, development, deployment). Some docs are in Russian.
+- **Coding:** Write tests first before implementing any functionality.
+- **Running tests:** When the user asks to run tests or to verify changes, use the run-tests skill: [.cursor/skills/run-tests/SKILL.md](.cursor/skills/run-tests/SKILL.md).

.cursor/skills/run-tests/SKILL.md

@@ -0,0 +1,53 @@
+---
+name: run-tests
+description: Runs backend (Go) and frontend (Vitest) tests for the hnh-map monorepo. Use when the user asks to run tests, verify tests, or after making code changes that should be validated.
+---
+
+# Run tests
+
+## When to run
+
+- User asks to run tests, run the test suite, or verify tests pass.
+- After implementing or changing code that should be validated by tests.
+
+## What to run
+
+This repo has two test suites. Run the one(s) that match the changed code, or both if unsure.
+
+### Backend (Go)
+
+From repo root:
+
+```bash
+make test
+```
+
+Or:
+
+```bash
+go test ./...
+```
+
+Uses temp dirs and in-memory DBs; no external services needed.
+
+### Frontend (Vitest)
+
+From repo root:
+
+```bash
+npm --prefix frontend-nuxt run test
+```
+
+Or from `frontend-nuxt/`:
+
+```bash
+npm test
+```
+
+## Scope
+
+- **Backend-only changes** (e.g. `internal/`, `cmd/`): run `make test`.
+- **Frontend-only changes** (e.g. `frontend-nuxt/`): run `npm --prefix frontend-nuxt run test`.
+- **Both or unclear**: run backend then frontend.
+
+Report pass/fail and any failing test names or errors.

.gitignore

@@ -23,6 +23,4 @@ frontend/dist
 
 # OS / IDE
 .DS_Store
-.cursor/*
-!.cursor/rules/
 .vscode/