feat: Implement DevicesHistory feature with triggers and history tracking

- Added db_history.py to manage DevicesHistory table and triggers for INSERT and UPDATE operations.
- Created device_history_instance.py for querying and grouping DevicesHistory records.
- Developed change_history.php for displaying device change history with filtering and pagination.
- Introduced skel_device_details_tab_history.php for skeleton loading state in device details tab.
- Added unit tests in test_device_history.py to validate trigger functionality and history management.
- Implemented filter population and pagination in the change history UI.

server/api_server/api_server_start.py

@@ -6,6 +6,7 @@ import os
 
 from flask import Flask, redirect, request, jsonify, url_for, Response
 from models.device_instance import DeviceInstance  # noqa: E402
+from models.device_history_instance import DevicesHistoryInstance  # noqa: E402
 from flask_cors import CORS
 from werkzeug.exceptions import HTTPException
 
@@ -772,6 +773,20 @@ def api_devices_totals(payload=None):
     return jsonify(device_handler.getTotals())
 
 
+@app.route("/devices/history/filters", methods=["GET"])
+@validate_request(
+    operation_id="get_device_history_filters",
+    summary="Get Device History Filter Values",
+    description="Return distinct changedBy and changedColumn values available in DevicesHistory. Optionally scope to a single device with ?devGuid=<guid>.",
+    tags=["devices"],
+    auth_callable=is_authorized
+)
+def api_devices_history_filters(payload=None):
+    dev_guid = request.args.get("devGuid") or None
+    filters = DevicesHistoryInstance().get_available_filter_values(devGUID=dev_guid)
+    return jsonify({"success": True, "data": filters})
+
+
 @app.route("/devices/totals/named", methods=["GET"])
 @validate_request(
     operation_id="get_device_totals_named",