fix(mpl): contain comm callback errors in mpl_interactive (#9532)

## Summary

A raising callback inside `mpl_interactive._handle_comm_msg` (e.g.
matplotlib's `AttributeError: 'Axes' object has no attribute
'_pan_start'` from `end_pan` without a prior `start_pan`) was
propagating up through `MarimoComm.handle_msg` →
`WIDGET_COMM_MANAGER.receive_comm_message` → the kernel's request
handler, terminating `asyncio.run` and killing the kernel subprocess.
The uvicorn parent kept serving so the UI just reported "stopped
responding".

This wraps the `handle_json` and `_handle_download` calls in `try/except
Exception` and logs via `LOGGER.exception` so a buggy callback is
contained while the traceback still surfaces for diagnosis.
`BaseException` is intentionally not caught.

Fixes the kernel-crash half of the matplotlib pan/zoom issue (see linked
Linear issue). The underlying matplotlib `_pan_start` bug is tracked
separately.

## Test plan

- [x] Manual repro via the linked Linear repro (pan → re-run cell → zoom
→ pan): exception logged, kernel stays alive, figure remains responsive.
- [x] Direct programmatic injection: `_handle_comm_msg` with a raising
`handle_json` returns cleanly and a follow-up message is processed.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: kirangadhave

marimo/_plugins/ui/_impl/from_mpl_interactive.py

@@ -299,23 +299,35 @@ def _handle_comm_msg(self, msg: dict[str, Any]) -> None:
             self._handle_download(fmt)
             return
         else:
-            # Forward to figure manager (mouse events, toolbar actions, etc.)
-            self._figure_manager.handle_json(event)  # type: ignore[no-untyped-call]
+            # Forward to figure manager (mouse events, toolbar actions, etc.).
+            # Swallow callback exceptions so a buggy handler can't kill the
+            # kernel subprocess; the exception propagates up through the comm
+            # manager and terminates asyncio.run otherwise.
+            try:
+                self._figure_manager.handle_json(event)  # type: ignore[no-untyped-call]
+            except Exception:
+                LOGGER.exception(
+                    "mpl_interactive handle_json failed for event type %s",
+                    msg_type,
+                )
 
     def _handle_download(self, fmt: str) -> None:
         """Render figure to the requested format and send back via comm."""
-        buf = io.BytesIO()
-        self._figure_manager.canvas.figure.savefig(
-            buf, format=fmt, bbox_inches="tight"
-        )
-        blob = buf.getvalue()
-        self._comm.send(
-            data={
-                "method": "custom",
-                "content": {"type": "download", "format": fmt},
-            },
-            buffers=[blob],
-        )
+        try:
+            buf = io.BytesIO()
+            self._figure_manager.canvas.figure.savefig(
+                buf, format=fmt, bbox_inches="tight"
+            )
+            blob = buf.getvalue()
+            self._comm.send(
+                data={
+                    "method": "custom",
+                    "content": {"type": "download", "format": fmt},
+                },
+                buffers=[blob],
+            )
+        except Exception:
+            LOGGER.exception("mpl_interactive download failed (fmt=%s)", fmt)
 
     def _convert_value(
         self, value: ModelIdRef | dict[str, Any]