tests: Add test scenario for SSD1327 OLED display.

Add a YAML test scenario file `tests/scenarios/ssd1327.yaml` for the SSD1327 driver.

### Expected tests
- **Mock**: verify initialization sequence
- **Hardware**: basic display operations (fill, text, show)
- **Manual**: validate display output visually

### Reference
- Driver: `lib/ssd1327/`
- Test framework: PR #28