test: add unit tests for KosliTemplateParser, KosliPolicyParser, and PolicyExpressionEvaluator

[MaximumTrainer]

Background

KosliTemplateParser, KosliPolicyParser, and PolicyExpressionEvaluator are new Spring components with no tests. They are critical to compliance evaluation.

Tasks

KosliTemplateParser

• Parse valid Kosli template YAML with trail-level and artifact-level attestations
• Parse template with ifCondition on an attestation
• Return null for blank/invalid YAML
• Handle missing version field (default to 1)

KosliPolicyParser

• Parse valid policy YAML with provenance.required: true
• Parse policy with trail-compliance.required: true
• Parse policy with attestations list including if condition
• Return null for blank/invalid YAML

PolicyExpressionEvaluator

• flow.name == "backend" matches correct flow name
• matches(artifact.name, "^backend.*") regex match
• exists(flow) returns true when flow name is set
• not, and, or compound expressions
• Malformed expression returns false (not exception)

Files

• backend/src/main/kotlin/com/factstore/application/template/KosliTemplateParser.kt
• backend/src/main/kotlin/com/factstore/application/policy/