fix(s51): close 2 review MINORs — non-UTF-8 skip + affected_codes parity

Both live in the tolerant inbox-read path and both contradicted the module's
own "skipped, never raised" / loader-parity docstrings (S5.1 review: ALLOW,
2 MINOR, non-gating):

- UnicodeDecodeError (a *.json hand-saved in Latin-1 with Norwegian æ/ø/å is
  invalid UTF-8) now SKIPPED in hitl._load_json_dict AND
  verdicts.load_verdicts_from_dir — was: crashed pending/route with a raw
  traceback (a ValueError subclass, caught by neither OSError nor
  JSONDecodeError). Fix symmetric across both readers.
- hitl._inbox_verdict_ids now skips a non-iterable affected_codes exactly as
  load_verdicts_from_dir does (frozenset() raises TypeError) — was: marked the
  proposal judged on key-presence alone → a silent false-negative in the
  operator pending queue. hitl-only: verdicts is the correct reference.

TDD: 3 RED-then-green (both UnicodeDecodeError twins + the parity gap) + 1
ground-truth pin locking the loader side so the parity cannot rot.

Gate: pytest → 389 passed, 4 skipped (was 385); ruff check + format clean; mypy clean.

tests/test_verdicts.py

@@ -7,6 +7,7 @@ genuine two-arg ``extend_instructions(source_id, instructions)`` GA signature
 Critical Fase 1 risk. Pattern: tests/spikes/test_d_verdictstore.py + real SessionContext.
 """
 
+import json
 import logging
 from pathlib import Path
 
@@ -205,6 +206,58 @@ def test_load_within_caps_is_unchanged(tmp_path) -> None:
     assert {v.decision for v in loaded} == {"approved", "rejected"}
 
 
+def test_load_skips_non_utf8_file(tmp_path) -> None:
+    """T-2.5d: a hand-authored inbox verdict saved in Latin-1 (Norwegian ``æ/ø/å``) is valid JSON bytes
+    but INVALID UTF-8; it matches the ``*.json`` glob yet must be SKIPPED, never raise — the loader's
+    per-file tolerant contract (the Step-7 loop relies on it). Detach the ``UnicodeDecodeError`` catch
+    → ``read_text(encoding='utf-8')`` raises → RED. The valid verdict alongside still loads."""
+    (tmp_path / "latin1.json").write_bytes(
+        json.dumps(
+            {
+                "id": "X",
+                "decision": "approved",
+                "rationale": "godkjent på møtet",
+                "proposal_features": {
+                    "affected_codes": ["05.2"],
+                    "measure_type": "m",
+                    "claimed_saving_nok": 200.0,
+                },
+            },
+            ensure_ascii=False,
+        ).encode("latin-1")
+    )
+    write_verdict(str(tmp_path), capture_verdict(_feats("Y"), "approved", "fine"))
+
+    loaded = load_verdicts_from_dir(str(tmp_path))
+    assert [v.decision for v in loaded] == ["approved"]  # latin1 file skipped, the valid one loads
+
+
+def test_load_skips_non_iterable_affected_codes(tmp_path) -> None:
+    """Parity ground-truth: ``verdict_from_dict``'s ``frozenset(affected_codes)`` raises ``TypeError``
+    on a non-iterable (``null``), and ``load_verdicts_from_dir`` SKIPS it. This pins the reference the
+    hitl inbox predicate mirrors (``test_hitl_loadbearing.test_inbox_idset_skips_non_iterable_affected_codes``)
+    so the parity contract cannot silently rot on the loader side."""
+    (tmp_path / "bad.json").write_text(
+        json.dumps(
+            {
+                "id": "X",
+                "decision": "approved",
+                "rationale": "r",
+                "proposal_features": {
+                    "affected_codes": None,
+                    "measure_type": "m",
+                    "claimed_saving_nok": 1.0,
+                },
+            }
+        ),
+        encoding="utf-8",
+    )
+    write_verdict(str(tmp_path), capture_verdict(_feats("Y"), "approved", "fine"))
+
+    loaded = load_verdicts_from_dir(str(tmp_path))
+    assert [v.decision for v in loaded] == ["approved"]  # non-iterable affected_codes skipped
+
+
 def test_no_inbox_json_uses_approved_with_adjustment() -> None:
     """Assumption 3 (TDD guard): no shipped/test ``.json`` uses the promotion-only decision
     ``approved_with_adjustment`` — the vocabulary SKIP would now silently drop it. It lives only in