Fixes the two live E2E blockers @ctaylor86 found on PR #77189 (macOS 26.3.1,
OpenSSL 3.6.3):
- retry the PKCS#12 export with -legacy when security import rejects the
OpenSSL 3 default format ('MAC verification failed during PKCS12 import')
- trust the self-signed root for the codeSign policy (security
add-trusted-cert -r trustRoot -p codeSign) — an imported-but-untrusted cert
is invisible to find-identity -v and unusable by codesign
- gate success on find-identity -v -p codesigning (postcondition), and use
the same -v probe for idempotency so an untrusted leftover cert is repaired
instead of reported as done
Tests rewritten as stateful fakes (valid only after import+trust), plus new
coverage for the -legacy retry, trust failure, postcondition gate, and the
untrusted-cert repair path; sabotage-verified (reverting to the name-in-output
probe fails 4 tests). Docs: manual fallback now includes the Trust step.
28f2ea86e2