// Now works:
let df = Frame.ReadCsv("(example.com/redacted)
let df = Frame.ReadCsv("https://raw.githubusercontent.com/user/repo/main/data.csv")

// Still works:
let df = Frame.ReadCsv("local/path/data.csv")

module private HttpReader =
    let private httpClient = lazy (new System.Net.Http.HttpClient())
    let openLocation (location: string) : System.IO.TextReader =
        if location.StartsWith("(redacted) StringComparison.OrdinalIgnoreCase) ||
           location.StartsWith("https://", StringComparison.OrdinalIgnoreCase) then
            let content = httpClient.Value.GetStringAsync(location).GetAwaiter().GetResult()
            new System.IO.StringReader(content) :> System.IO.TextReader
        else
            new System.IO.StreamReader(location) :> System.IO.TextReader
```

- `HttpClient` is shared via a `lazy` static instance to avoid socket exhaustion.
- `GetAwaiter().GetResult()` keeps `ReadCsv` synchronous — no change to callers.
- `StringReader` only needs the already-fetched string, so the `HttpClient` lifetime is irrelevant after the fetch.
- All three `ReadCsv` path/location overloads are updated: the C# extension and both F# extensions.

## Test Status

```
Passed! - Failed: 0, Passed: 669, Skipped: 0, Total: 669