Update test scripts and documentation for simplified OpenTelemetry approach

- Update all test scripts to use OTEL_EXPORT_ENABLED instead of legacy flags
- Remove references to deprecated ENABLE_OPENTELEMETRY and OTEL_ENABLED
- Simplify run_tests_local.sh to use --exclude-tag=bluesky
- Update documentation to reflect instrumentation always enabled
- Remove legacy configuration section from README.md

All scripts now use the new approach where:
- OpenTelemetry instrumentation is always enabled
- Only data export is controlled by OTEL_EXPORT_ENABLED flag
- Cleaner configuration with single export control flag

scripts/run_tests_with_coverage.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 """
-Run tests with OpenTelemetry enabled and coverage measurement.
+Run tests with OpenTelemetry instrumentation and export enabled, plus coverage measurement.
 This script is designed to be used with 'coverage run' command.
 """
 
@@ -13,14 +13,13 @@ from django.test.utils import get_runner
 
 
 def main():
-    # Enable OpenTelemetry
-    os.environ["ENABLE_OPENTELEMETRY"] = "true"
-    os.environ["OTEL_ENABLED"] = "true"
+    # Enable OpenTelemetry instrumentation and export
+    os.environ["OTEL_EXPORT_ENABLED"] = "true"
     os.environ["OTEL_SERVICE_NAME"] = "ivatar-test"
     os.environ["OTEL_ENVIRONMENT"] = "test"
 
-    print("Running tests with OpenTelemetry enabled...")
-    print("==========================================")
+    print("Running tests with OpenTelemetry instrumentation and export enabled...")
+    print("====================================================================")
 
     # Add current directory to Python path
     sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
@@ -41,7 +40,9 @@ def main():
         return 1
     else:
         print("")
-        print("Tests completed successfully (OpenTelemetry enabled)")
+        print(
+            "Tests completed successfully (OpenTelemetry instrumentation and export enabled)"
+        )
         return 0