feat(signal): adding historical events to signal definitions

[whitdog47]

This pull request introduces the capability to log and view create and update events associated with signal definitions. This enhancement allows users to track changes and updates to signals over time, providing greater transparency and traceability.

Key Changes

• Database Schema Update:

  • Added a new column signal_id to the event table to establish a relationship between events and signals.
  • Created a foreign key constraint to ensure referential integrity.

• Model Updates:

  • Updated the Event and Signal models to include relationships for tracking events.

• Service Enhancements:

  • Introduced log_signal_event function to log events related to signal creation and updates.
  • Modified create and update functions in the signal service to log events whenever a signal is created or updated.

• API Changes:

  • Updated the create_signal and update_signal endpoints to include the current user, enabling event logging with user context.

• Frontend Additions:

  • Added a new HistoryViewer.vue component to display the timeline of events for a signal.
  • Integrated the history viewer into the signal table, allowing users to view the history of a signal directly from the table interface.

Sample screenshot