fix(python): surface Function drop warnings (#4880)

Remote Python `drop_function` currently discards the dependent-view
warnings returned by SQL DROP. Both the synchronous and coroutine APIs
now emit those warnings through `warnings.warn` while preserving their
boolean result and executing DROP once. The server support is already
merged in lancedb/sophon#9820.

The Rust decoder reads warnings across every result batch, including an
empty first batch. Missing warning columns remain compatible with older
servers; malformed or null warning lists are rejected. The hidden
binding bridge carries the warnings to Python. The separate
`drop_function_async` API and its `(bool, Job)` contract are unchanged.
Python warning filters can raise after the catalog mutation has
completed.

Validation: a compiled PyO3/public-server reproduction failed before the
fix and passed afterward; the public async path also returned `true`
with the expected dependent-view warning. Final source passes two
focused Rust tests, two Python wrapper tests, strict targeted Clippy,
formatting, and Ruff. Three decoder tests cover batch/null/type and
older-server behavior. The public runs preceded a two-file
simplification of the completed Job projection; focused final-source
checks cover that delta. Current-main integration is conflict-free, and
its overlapping changes concern independent retry-policy APIs/tests.

Documentation now covers warning filters, the post-removal
warnings-as-errors behavior, and silent compatibility with older
servers. The follow-up changes only prose and a Python docstring; the
runtime validation above remains applicable.

Refs ENT-3659. Whole-issue independent acceptance remains pending.

python/src/connection.rs

@@ -928,6 +928,23 @@ impl Connection {
         })
     }
 
+    #[pyo3(signature = (name, version, namespace_path=None))]
+    pub fn _drop_function_with_warnings(
+        self_: PyRef<'_, Self>,
+        name: String,
+        version: String,
+        namespace_path: Option<Vec<String>>,
+    ) -> PyResult<Bound<'_, PyAny>> {
+        let inner = self_.get_inner()?.clone();
+        let namespace_path = namespace_path.unwrap_or_default();
+        future_into_py(self_.py(), async move {
+            inner
+                .drop_function_with_warnings(name, version, &namespace_path)
+                .await
+                .infer_error()
+        })
+    }
+
     #[pyo3(signature = (name, version, namespace_path=None))]
     pub fn drop_function_async(
         self_: PyRef<'_, Self>,