test(maturity): split markdown reader assertions

[boshu2]

Summary

• Split the markdown readLearningData test cases into focused helper assertions.
• Preserve the existing subtest names and behavior while clearing the local gocyclo >10 scout finding in maturity_test.go.

Bead

• na-uuy.6.6

Validation

• gocyclo -over 10 cli/cmd/ao/maturity_test.go
• env -u AGENTOPS_RPI_RUNTIME go test ./cmd/ao -run 'TestMaturity_readLearningData_Markdown' -count=1\n- env -u AGENTOPS_RPI_RUNTIME go test ./cmd/ao -run 'TestMaturity_readLearningData' -count=1\n- git diff --check\n- env -u AGENTOPS_RPI_RUNTIME scripts/pre-push-gate.sh --fast\n