docs(configuration): reference table missing total_timeout, ws_ping_interval, ws_close_timeout, allow_unknown_host #300

Summary

The KalshiConfig field reference table in docs/configuration.md:32-46 omits four documented dataclass fields:

allow_unknown_host is partially covered by the prose under URL validation (lines 66-77) but is not in the at-a-glance reference table users actually skim. The other three predate v2.5 but have never appeared in the reference table.

Users reaching for total_timeout (the wall-clock retry budget #193 introduced) or ws_ping_interval (heartbeat tuning) currently have to discover them by reading the dataclass source — defeats the purpose of the doc page.

Suggested fix

Append these rows to the table at docs/configuration.md:46:

| `total_timeout` | `None` | Wall-clock cap (seconds) across the whole request including all retries. `None` = unbounded; cap with the per-attempt `timeout` only. See [Retries & idempotency](retries.md). |
| `ws_ping_interval` | `20.0` | Seconds between WebSocket pings (forwarded to the `websockets` library). |
| `ws_close_timeout` | `5.0` | Seconds to wait for a clean WebSocket close handshake before forcing the socket shut. |
| `allow_unknown_host` | `False` | When `False`, the SDK rejects `base_url` / `ws_base_url` whose host is not in the known-Kalshi allowlist (`api.elections.kalshi.com`, `demo-api.kalshi.co`) or a loopback host. Opt out via the field or `KALSHI_ALLOW_UNKNOWN_HOST=1` if you target a custom proxy. (Added in v2.5.0 #250.) |

Optionally tighten the URL validation section to point at the new allow_unknown_host row instead of repeating its description.

Discovered by

Post-v2.5 multi-reviewer audit (Docs / configuration reference surface).