feat(shadbala): BPHS minimum check first, bands labelled as the site's (T3, BUG-1208)

Astrologer ruling 甲13. New scripts/shadbala_display.py (display only; shadbala.py is
frozen and unchanged): chart.shadbala now carries min_required, meets_minimum,
minimum_check (达到/未达到 BPHS 最低要求), level_source=site_band and level
'<band>（网站分档）'; report Shadbala table gains 'BPHS minimum' and 'Site band'
columns (zh/en); evidence snapshot ranking and health narrative say the minimum
check first and mark the band as the site's.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N4f2nya58RoRu4yEmJgRGE

scripts/shadbala_display.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+"""How a Shadbala strength is shown (astrologer rulings 2026-10-03 甲13, BUG-1208).
+
+First whether the planet meets the BPHS minimum (BPHS ch. 27 vv. 32-33, the
+`shadbala.MIN_REQUIRED` table), then the site's own band (150/125/100/75/50 % of
+that minimum -> 极强…极弱), labelled as the site's band. `shadbala.py` is in the
+frozen rectification identity, so the fields are added here, at display time,
+from values the engine already returns; nothing is recomputed.
+"""
+
+from __future__ import annotations
+
+from typing import Any, Dict, Optional
+
+LEVEL_SOURCE = 'site_band'
+SITE_BAND_SUFFIX = '（网站分档）'
+SITE_BAND_SUFFIX_EN = ' (site band)'
+MEETS_ZH = '达到 BPHS 最低要求'
+MISSES_ZH = '未达到 BPHS 最低要求'
+MEETS_EN = 'meets the BPHS minimum'
+MISSES_EN = 'below the BPHS minimum'
+
+
+def _number(value: Any) -> Optional[float]:
+    return float(value) if isinstance(value, (int, float)) and not isinstance(value, bool) else None
+
+
+def minimum_fields(rupas: Any, min_required: Any, band: Any) -> Dict[str, Any]:
+    """`min_required`, `meets_minimum`, `minimum_check`, band label and source."""
+    total = _number(rupas)
+    minimum = _number(min_required)
+    meets = None if total is None or minimum is None else total >= minimum
+    fields: Dict[str, Any] = {
+        'min_required': minimum,
+        'meets_minimum': meets,
+        'minimum_check': None if meets is None else (MEETS_ZH if meets else MISSES_ZH),
+        'level_source': LEVEL_SOURCE,
+    }
+    if band not in (None, ''):
+        fields['level'] = f'{band}{SITE_BAND_SUFFIX}'
+    return fields
+
+
+def row_fields(row: Dict[str, Any]) -> Dict[str, Any]:
+    """Display fields for one `shadbala.calc_shadbala` planet row."""
+    return minimum_fields(row.get('total_rupas', row.get('rupas')), row.get('min_required'), row.get('strength_level'))
+
+
+BAND_EN = {'极强': 'very strong', '强': 'strong', '充足': 'adequate', '略弱': 'slightly weak', '弱': 'weak', '极弱': 'very weak'}
+
+
+def band_text(band: Any, language: str = 'zh') -> Optional[str]:
+    if band in (None, ''):
+        return None
+    if language == 'en':
+        return f"{BAND_EN.get(str(band), str(band))}{SITE_BAND_SUFFIX_EN}"
+    return f'{band}{SITE_BAND_SUFFIX}'
+
+
+def check_text(meets: Optional[bool], language: str = 'zh') -> str:
+    if meets is None:
+        return '-'
+    if language == 'en':
+        return MEETS_EN if meets else MISSES_EN
+    return MEETS_ZH if meets else MISSES_ZH