Update library metadata and enhance module lifecycle safety

[Burki24]

This pull request introduces a comprehensive "review hardening" of the OpenShutterButtonControl library, focusing on robust initialization, improved configuration validation, safer runtime behavior, and enhanced user feedback. The changes ensure that all variable types and actions are correctly validated both in the configuration form and at runtime, movements are safely stopped in all relevant situations, and users receive clear status messages on configuration issues.

Configuration and Validation Improvements

• The configuration form (form.json) now restricts selectable variable types for button, movement, and position variables, and enforces required actions for movement and position variables. [1] [2]
• At runtime, the module validates variable types and actions, and registers all configured variables as Symcon object references, updating them cleanly on changes. [1] [2] [3] [4]
• The long-press threshold property is now validated to be within 100–5000 ms, both in the UI and in code. [1] [2] [3]

Runtime Safety and Movement Handling

• Initialization of external variables is deferred until the Symcon kernel is fully ready; all movement is safely stopped on button release, configuration changes, or instance deletion. The movement is stopped on the exact variable that started it, preventing duplicate or missed STOP commands. [1] [2] [3] [4] [5]
• Delayed timer execution is handled robustly, ensuring a complete sequence of OPEN/CLOSE and STOP commands even if the timer fires late.

User Feedback and Status Messaging

• The module provides detailed status codes and messages for all major configuration errors (e.g., missing/invalid variables, missing actions, invalid property values, incomplete configuration), both in the UI and as Symcon instance status. [1] [2] [3]
• The README and changelog are updated with clear explanations of the new validation logic, status codes, and runtime behavior. [1] [2] [3] [4]

Other Enhancements

• Regression tests for kernel startup, variable actions, properties, references, and safe movement termination have been added (as noted in the changelog).
• The static version badge is replaced with a dynamic GitHub release badge.

These changes collectively make the module much more robust, user-friendly, and safe to operate in production environments.