Tests for alert filter evaluation logic:
- evaluateVMCondition: metric/text/raw conditions for VMs
- evaluateContainerCondition: same for containers
- evaluateFilterStack: AND/OR logic with multiple conditions
- evaluateFilterCondition: type dispatch
74 test cases covering:
- All metric types (cpu, memory, disk, diskread, diskwrite, network)
- All comparison operators (>, <, >=, <=, =, ==)
- Text search fields (name, node, vmid) with case insensitivity
- Raw text search across multiple fields
- Value type conversions (int to float64)
- Edge cases (zero, empty, invalid types)
Coverage improved from 46.8% to 48.9%.