• feat: add External Heartbeat Ping URL (#2700)
• fix(service): move constructor guard clauses outside try-catch to prevent premature runner crash
• fix(service): wrap masking regex value patterns in atomic groups to eliminate ReDoS timeouts
• fix(service): move state cleanup inside the lock boundary to eliminate telemetry snapshot sync races
• fix(ui): BulkObservableCollectionTests.cs - TrimToSize_NonListImplementation_UsesManualLoop never reaches the manual-loop branch: every ObservableCollection ctor copies into a List (#3129)