S5.4 review MINOR (SC5 fail-fast hole, run.py:740). A valid-JSON but
wrong-shape savings ledger escaped the --report fail-fast refusal:
- top-level {} iterated zero keys -> entries=[] -> rc 0 "0,00 kr"
(a malformed file masquerading as a real zero-savings result)
- a bare scalar / object-with-keys / list-of-non-objects raised an
uncaught TypeError -> traceback (violates SC5 "rc 1, no traceback")
Fix at the fail-fast boundary, not the run.py except tuple: the review's
first option (add TypeError to run.py:740) leaves the {} masquerade
because {} is an empty iteration, not a TypeError. SavingsLedger.load now
raises ValueError for a non-array top-level and a non-object row, caught
by run.py:740's existing ValueError arm. Hardens both callers
(run.py:740 report + run.py:785 portfolio).
RED-first: 6 unit cases (test_ledger) + 2 CLI rc-1 cases (test_run_cli).
452 passed; ruff + mypy clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KNNiJRk1sSwxgVLS5AobT1
