Add M17.6 coverage gates

[jmjava]

Summary

• enforce full-source Python coverage floors in the prescribed regression suite
• add focused tests for orchestrator graph/Kubernetes clients and GUI Kubernetes/repository paths
• enforce independent operator pipeline and controller coverage floors in operator CI and language regression
• add static acceptance checks for coverage-gate wiring
• record M17.6 completion evidence

Targets and measured results

• orchestrator: 97.18% (floor 92%)
• management GUI backend: 92.26% (floor 91%)
• tekton-dag-common: 83.45% (floor 83%)
• baggage Python: 88.14% (floor 88%)
• operator pipeline: 80.0% (floor 80%)
• operator controller: 32.6% (floor 32%)

Verification

• focused Python coverage suites pass (326 tests total)
• operator package coverage gate passes
• prescribed local regression exited 0 (Tekton/Newman/Results unavailable without a Kubernetes context)
• final CI runs 34909521809 and 34909521864 passed all five checks, including coverage, language tests, lint, envtest, and Kind domain E2E