test: final source recheck for V1 jet CV and V3 Taylor-Green runs

Both runners now re-derive the recorded source identity after the run
(source_provenance.final_source_check) and only then mark the receipt
complete. A changed source, or a recheck that fails, rewrites the receipt
as invalid and raises:
- V1: in-run receipts carry run_status=INCOMPLETE; finish_receipt sets
  COMPLETE or INVALID_SOURCE_CHANGED (+ source_recheck/source_after).
- V3: completed stays False, invalid=SOURCE_CHANGED_DURING_RUN, no
  screening_pass; the assessor requires source_recheck UNCHANGED (frozen
  mode still accepts receipts from before the field existed).
Interrupted runs keep INCOMPLETE / completed=False. Host tests cover
unchanged, changed and failed rechecks and incomplete runs. No threshold
or solver change.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/validation/taylor_green/assess_projected_pairs.py

@@ -144,6 +144,10 @@ def assess(records, expected_revision=None, current=False):
             checks[label + " reference"] = (r.get("numerical_revision") == NUMERICAL_REVISION
                                              and "source_mode" not in r
                                              and r.get("reference_harness") == REFERENCE_HARNESS)
+        # Final source recheck (run_case); receipts from before it existed carry no field
+        # and are accepted only in the frozen mode.
+        recheck = r.get("source_recheck") if current else r.get("source_recheck", "UNCHANGED")
+        checks[label + " source_recheck"] = recheck == "UNCHANGED" and "invalid" not in r
         checks[label + " numerics"] = r.get("numerics") == NUMERICS and r.get("initialization") == INITIALIZATION
         runtime = r.get("runtime_source", {})
         package = Path(runtime.get("checkout", "")) / "src/CelerisLab"