fetchPcrIntraday abstract method
Historical Put/Call OI ratio, pre-computed per strike range, so the Analysis screen's PCR tab can show its full session range immediately
JSON array, oldest first:
[
{
"time": 1721460600000,
"price": 24230.5,
"pcr": { "3": 0.42, "5": 0.51, "10": 0.63, "20": 0.7, "all": 0.75 }
},
...
]
Return "[]" when no historical data is available.
Implementation
Future<String> fetchPcrIntraday();