feat(scenario): step output, getStepOutput helper, export/import MCP tools, doc restructure

- add output column to ScenarioRunStepEntity; exec step return value is JSON-serialised and stored
- expose helpers.getStepOutput(order) in exec code; negative order is relative to current step
- add get_scenario_run, wait_for_scenario_run, export_scenario, import_scenario MCP tools
- move Architecture, Key descriptors, MCP tools, Scenario, Development docs to docs/
- delete CONTRIBUTING.md (replaced by docs/development.md)

docs/development.md

@@ -0,0 +1,143 @@
+# Development
+
+## Prerequisites
+
+- Node.js 20+
+- Docker + Docker Compose
+
+Install dependencies:
+
+```bash
+npm install
+npx playwright install chromium   # first time only
+```
+
+Copy `.env.example` to `.env` and fill in the required values before running.
+
+### Environment variables
+
+| Variable | Default | Description |
+|---|---|---|
+| `PORT` | `3000` | HTTP port |
+| `KEYS_DIR` | `keys` | Directory containing `*.json` key descriptors |
+| `DB_PATH` | `data/sessions.db` | SQLite database file |
+| `PLAYWRIGHT_CHROMIUM_EXECUTABLE_PATH` | _(Playwright default)_ | Path to Chromium binary. Set automatically in Docker (`/usr/bin/chromium`). |
+
+---
+
+## Starting the application
+
+**Development** (watch mode, restarts on file changes):
+
+```bash
+npm run start:dev
+```
+
+**Production build, then start**:
+
+```bash
+npm run build
+npm run start:prod
+```
+
+The application listens on port **3000** by default.
+
+---
+
+## Running tests
+
+```bash
+npm run test
+```
+
+Run a single spec file:
+
+```bash
+npm run test -- --no-coverage test/scenario.controller.spec.ts
+```
+
+Watch mode:
+
+```bash
+npm run test:watch
+```
+
+Enable verbose NestJS log output during tests:
+
+```bash
+npm run test:debug
+```
+
+---
+
+## Formatting code
+
+[Prettier](https://prettier.io/) is used to format all TypeScript source and test files:
+
+```bash
+npm run format
+```
+
+This rewrites `src/**/*.ts` and `test/**/*.ts` in place.
+
+---
+
+## Linting
+
+[ESLint](https://eslint.org/) with `typescript-eslint` and `eslint-config-prettier` is used:
+
+```bash
+# report issues
+npm run lint
+
+# report and auto-fix where possible
+npm run lint:fix
+```
+
+The project targets zero errors. Run lint before committing.
+
+---
+
+## Building the container
+
+```bash
+docker compose build
+```
+
+To rebuild without the layer cache:
+
+```bash
+docker compose build --no-cache
+```
+
+---
+
+## Running with Docker Compose
+
+Start (detached):
+
+```bash
+docker compose up -d
+```
+
+Build and start in one step:
+
+```bash
+docker compose up -d --build
+```
+
+The application is exposed at **http://localhost:13000**.
+
+SQLite data is persisted in `./data/` and key files are mounted from `./keys/` — both directories are volume-mounted into the container.
+
+Stop and remove containers:
+
+```bash
+docker compose down
+```
+
+View logs:
+
+```bash
+docker compose logs -f
+```