code-modernization: no "not applicable" path for Same behavior / Fresh inputs on reimagine services with no legacy counterpart

Plugin: code-modernization 1.0.0, scripts/proof_pack.py (checks 3 "Same behavior" and 4 "Fresh inputs").

What happens: on the reimagine track some services have no counterpart in the legacy system at all, so there is no legacy output to compare with: deployment charts and the migration hook, CI/ops scripts, an offline-sync protocol the legacy never had, a browser e2e harness. For each of them the pack reports

• "Same behavior: No equivalence cases were recorded: the new code was never compared with the legacy output."
• "Fresh inputs: The fresh-input check was not run: no equivalence/fresh-cases.json."

and the module can never be PROVEN, even with all tests passing and a canary shown. The only ways to "fix" it are to invent comparison cases that compare nothing, or to fold the service into another module.

Expected: a way for a person (not the agent) to mark a module "no legacy counterpart", with a reason, so checks 3 and 4 become na and the declaration is listed in VERIFICATION.md for sign-off. For example {"notApplicable": "<reason>", "approvedBy": "<name>", "date": "<date>"} in equivalence/<module>/cases.json, read by the pack like approvedDifference is today. Without the declaration, today's behavior stays.

Repro: a reimagine system with a deploy/ (Helm charts + one migration script with unit tests) service; run modernize-verify; the service is PARTLY PROVEN with the two reasons above regardless of evidence.

Related: #6898 (the same services also fail "Rules traced" because no rule is tied to them).