chore(streamlit): migrate components.v1.html → st.iframe (deprecation)

Streamlit logs a deprecation notice on every render:

  Please replace ``st.components.v1.html`` with ``st.iframe``.
  ``st.components.v1.html`` will be removed after 2026-06-01.

Replace all 9 call sites (6 tool pages + 3 in ``_legacy.py``).
Both APIs feed ``srcdoc`` to the underlying iframe so the
HTML/JS payload and the cross-frame DOM access pattern
(``window.parent.document``) are unchanged.

``st.iframe`` rejects ``height=0`` (raises ``StreamlitInvalid
HeightError``), so bump every zero-height call to ``height=1``.
1px is effectively invisible — these are script-only iframes, no
visible payload — and avoids the validator.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/gui/pages/5_Column_Mapper.py

@@ -476,8 +476,7 @@ with dl_c:
 # unrelated widgets in the Results section don't yank the viewport back
 # to the top of Results.
 if st.session_state.pop("_colmap_scroll_to_results", False):
-    from streamlit.components.v1 import html as _components_html
-    _components_html(
+    st.iframe(
         """
         <script>
           const doc = window.parent.document;
@@ -485,5 +484,5 @@ if st.session_state.pop("_colmap_scroll_to_results", False):
           if (target) target.scrollIntoView({behavior: 'smooth', block: 'start'});
         </script>
         """,
-        height=0,
+        height=1,
     )