Resolved configuration after Update 6: blackout_day is 2026-11-01 and priority_high_first is true. All other keys keep their earlier values.

Interpretation choices:
- Cancelled appointments go through the same validity pipeline as the rest. An invalid one is rejected. A valid one that fits capacity goes to blocked.
- Ids are sorted by plain string comparison. Non-string ids are sorted by `str(id)` as a fallback.
- Conflicting appointments go to rejected.

Implementation notes:
- Deduplication with the "first" policy keeps the first row's values and its original index, and the retained position stays at the first insertion.
- Processing order is priority descending, with ties broken by original index.
- Overlap is computed on UTC instants. With adjacency allowed, intervals overlap only when `s < e2 and s2 < e`.

```json
{"files": {"main.py": "from core import run\nfrom policy import POLICY\ndef evaluate(payload):\n    return run(payload, POLICY)\n", "policy.py": "POLICY = {\n    'timezone': 'America/New_York',\n    'cutoff_hour': 17,\n    'cutoff_inclusive': True,\n    'lead_minutes': 30,\n    'adjacency_allowed': True,\n    'cancelled_blocks': True,\n    'duplicate_policy': 'first',\n    'duration_max': 120,\n    'capacity': 1,\n    'report_order': 'id',\n    'blackout_day': '2026-11-01',\n    'priority_high_first': True,\n}\n", "helpers.py": "from datetime import datetime, timedelta\nfrom zoneinfo import ZoneInfo\n\n\ndef parse_dt(s):\n    if isinstance(s, str) and s.endswith('Z'):\n        s = s[:-1] + '+00:00'\n    return datetime.fromisoformat(s)\n\n\ndef overlaps(a, b, adjacency_allowed):\n    s1, e1 = a\n    s2, e2 = b\n    if adjacency_allowed:\n        return s1 < e2 and s2 < e1\n    return s1 <= e2 and s2 <= e1\n\n\ndef sort_ids(items, order):\n    # items: list of (id, index)\n    if order == 'input':\n        return [i for i, _ in sorted(items, key=lambda t: t[1])]\n    return [i for i, _ in sorted(items, key=lambda t: (str(t[0]) if not isinstance(t[0], str) else t[0], t[1]))]\n", "core.py": "from datetime import timedelta\nfrom zoneinfo import ZoneInfo\nfrom helpers import parse_dt, overlaps, sort_ids\n\n\ndef run(payload, policy):\n    tz = ZoneInfo(policy['timezone'])\n    now = parse_dt(payload['now'])\n    rows = payload.get('appointments', [])\n\n    kept = {}\n    order = []\n    for idx, a in enumerate(rows):\n        k = a['id']\n        if k not in kept:\n            order.append(k)\n            kept[k] = (idx, a)\n        elif policy['duplicate_policy'] == 'last':\n            kept[k] = (idx, a)\n    entries = [(kept[k][0], kept[k][1]) for k in order]\n\n    hi = policy['priority_high_first']\n    if hi:\n        entries.sort(key=lambda t: (-t[1]['priority'], t[0]))\n    else:\n        entries.sort(key=lambda t: (t[1]['priority'], t[0]))\n\n    earliest = now + timedelta(minutes=policy['lead_minutes'])\n    accepted = []\n    sel, blk, rej = [], [], []\n\n    for idx, a in entries:\n        aid = a['id']\n        dur = a['duration']\n        ok = True\n        if not (dur > 0 and dur <= policy['duration_max']):\n            ok = False\n        start = parse_dt(a['start'])\n        if ok and start < earliest:\n            ok = False\n        if ok:\n            ls = start.astimezone(tz)\n            if ls.date().isoformat() == policy['blackout_day']:\n                ok = False\n        if ok:\n            end = start + timedelta(minutes=dur)\n            cutoff = ls.replace(hour=policy['cutoff_hour'], minute=0, second=0, microsecond=0)\n            if policy['cutoff_inclusive']:\n                ok = end <= cutoff\n            else:\n                ok = end < cutoff\n        if ok and a.get('cancelled') and not policy['cancelled_blocks']:\n            ok = False\n        if not ok:\n            rej.append((aid, idx))\n            continue\n        iv = (start, end)\n        n = sum(1 for x in accepted if overlaps(iv, x, policy['adjacency_allowed']))\n        if n >= policy['capacity']:\n            rej.append((aid, idx))\n            continue\n        accepted.append(iv)\n        if a.get('cancelled'):\n            blk.append((aid, idx))\n        else:\n            sel.append((aid, idx))\n\n    ro = policy['report_order']\n    return {\n        'selected': sort_ids(sel, ro),\n        'blocked': sort_ids(blk, ro),\n        'rejected': sort_ids(rej, ro),\n    }\n"}}
```