cenno v0.2.0

Added

• Slider catalog control (standard SliderApi + minLabel/maxLabel/ selectAction): continuous "how much" answers, committing on thumb release or Enter.
• DateTimeInput catalog control (standard API + submitAction): native date/time pickers for "when?" answers. - Image catalog control (standard ImageApi): display-only visual context in prompts.
• In-app updates from GitHub releases via the Tauri updater, with Check for updates… in the tray menu (signature-verified; installs and restarts only after confirmation).
• docs/design/CONTROLS.md: the catalog inventory and the recipe for adding controls.
• Repository meta: LICENSE (Apache-2.0), NOTICE, AUTHORSHIP, SECURITY, CONTRIBUTING, CODE_OF_CONDUCT, CHANGELOG.