feat(plotly): add reactive funnel and funnelarea selection support (#9044)

## 📝 Summary

Adds click-based selection support for `funnel` and `funnelarea` Plotly
trace types, making them fully reactive in `mo.ui.plotly`.

## 🔍 Description of Changes

- **Frontend**: `shouldHandleClickSelection` now handles `"funnel"` and
`"funnelarea"` clicks; `extractPoints` returns trace-appropriate fields
(`x`, `y`, `label`, `value`, percentages for funnel; `label`, `value`,
percentages for funnelarea — no x/y)
- **Backend**: `_convert_value` dispatches to
`_append_funnel_points_to_selection` and
`_append_funnelarea_points_to_selection`; range selections extract
stages by value overlap; click selections pass through with index resync
- **Example**: `examples/third_party/plotly/funnel_chart.py` with
`px.funnel`, multi-trace regional funnel, and `go.Funnelarea`

## Selection
<img width="946" height="661" alt="funnel"
src="https://github.com/user-attachments/assets/48b8a48f-c4c9-4943-a873-756f62ef2be4"
/>

## 📋 Pre-Review Checklist
<!-- These checks need to be completed before a PR is reviewed -->

- [ ] For large changes, or changes that affect the public API: this
change was discussed or approved through an issue, on
[Discord](https://marimo.io/discord?ref=pr), or the community
[discussions](https://github.com/marimo-team/marimo/discussions) (Please
provide a link if applicable).
- [x] Any AI generated code has been reviewed line-by-line by the human
PR author, who stands by it.
- [x] Video or media evidence is provided for any visual changes
(optional). <!-- PR is more likely to be merged if evidence is provided
for changes made -->

## ✅ Merge Checklist

- [x] I have read the [contributor
guidelines](https://github.com/marimo-team/marimo/blob/main/CONTRIBUTING.md).
- [x] Documentation has been updated where applicable, including
docstrings for API changes.
- [x] Tests have been added for the changes made.

@mscolnick @nojaf

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: axsseldz

examples/third_party/plotly/funnel_chart.py

@@ -2,8 +2,8 @@
 # requires-python = ">=3.10"
 # dependencies = [
 #     "marimo",
-#     "pandas==2.3.0",
-#     "plotly==6.0.1",
+#     "pandas==2.3.3",
+#     "plotly==6.5.1",
 # ]
 # ///