feat(remote): discover server builds and retain error provenance (#4999)

Remote callers can use `db.server_info()` in Rust and Python, including
synchronous and asynchronous Python connections, to identify the
responding server without submitting a query or Job. Typed results
describe the query-node build, component versions, Function protocol and
configured images. Older servers without the endpoint return an explicit
unsupported error.

REST and Flight errors retain the reported build in diagnostic text and
Rust `RemoteErrorMetadata.server`. Typed table/job-not-found errors
preserve their HTTP source and classification, including the
schema-cache path; masked REST errors can obtain provenance from the
response header. Unknown build information stays absent.

The matching native Python SDK was exercised against a real localhost
server (`8829b074` client / `43920fa` server): sync/async discovery,
both SQL version forms and actual REST/Flight error provenance passed.
The product files match this branch; private validation drivers are
excluded. Focused coverage includes typed 404 errors, masked errors, and
the public schema-cache regression. Deployment and published-package
acceptance remain separate.

Server counterpart: https://github.com/lancedb/sophon/pull/10234.

Related: ENT-3565.

python/src/connection.rs

@@ -1285,6 +1285,14 @@ impl Connection {
         ))
     }
 
+    pub fn server_info(self_: PyRef<'_, Self>) -> PyResult<Bound<'_, PyAny>> {
+        let inner = self_.get_inner()?.clone();
+        future_into_py(self_.py(), async move {
+            let info = inner.server_info().await.infer_error()?;
+            serde_json::to_string(&info).map_err(|error| PyValueError::new_err(error.to_string()))
+        })
+    }
+
     pub fn list_gpu_classes(self_: PyRef<'_, Self>) -> PyResult<Bound<'_, PyAny>> {
         let inner = self_.get_inner()?.clone();
         future_into_py(self_.py(), async move {