merge origin/staging into api chart subprocess gate (issue #64)

Docs-only catch-up; agent-loop rule A.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LutgzyJqNhPpZy1nFsJtN3

scripts/jyotish_api_server.py

@@ -2589,12 +2589,24 @@ def _vedastro_runtime_fingerprint() -> dict:
     }
 
 
+def _chart_ascendant_nakshatra(ascendant_data: dict, lon: float) -> dict:
+    """Keep the engine's nakshatra fields when /api/chart rebuilds the ascendant."""
+    fields = {
+        key: ascendant_data[key]
+        for key in ('nakshatra', 'nakshatra_pada', 'nakshatra_lord')
+        if ascendant_data.get(key) not in (None, '')
+    }
+    if 'nakshatra' in fields:
+        return fields
+    return _load_local_module('jyotish_engine')._nakshatra_fields(lon)
+
+
 def _build_api_chart_cache_payload(body: dict) -> dict:
     import api_scratch_retention as retention
 
     today = body.get('today') or body.get('current_date')
     return {
-        'cache_schema_version': 6,
+        'cache_schema_version': 7,
         'birth': retention.normalize_chart_cache_birth(body),
         'calculation': {
             'ayanamsa': _request_ayanamsa(body),
@@ -6659,6 +6671,7 @@ class JyotishAPIHandler(BaseHTTPRequestHandler, VedastroEvidenceMixin, SynastryM
                     'degree': round(asc_lon % 30, 2),
                     'degree_in_sign': round(asc_lon % 30, 2),
                     'lon': round(asc_lon, 4),
+                    **_chart_ascendant_nakshatra(ascendant_data, asc_lon),
                 },
                 'planets': planets_data, 'houses': houses, 'shadbala': shadbala_summary,
                 'dasha': {