Open HTML files in browser instead of rendering inline in Streamlit reports

[Copilot]

Viewing complex HTML files (e.g., MultiQC reports, interactive plots) inline via st.components.v1.html() is constrained by fixed height, sandboxed rendering, and poor UX for large files. This replaces inline rendering with a link button that opens the HTML in a new browser tab.

Changes

• _generate_html_content: Replaces st.components.v1.html() with st.link_button("Open in browser", ...):
  • Local files: Base64-encodes content into a data:text/html;base64,... URI; emits st.warning for files >5MB that may not open in all browsers
  • URLs: Links directly to the URL — no longer fetches and embeds content
• _generate_component_imports: Adds import base64 for HTML components
• Test fixtures in tests/report_examples/ regenerated to match new output

Generated code example (local file)

file_path = (section_dir / 'path/to/report.html').resolve().as_posix()
with open(file_path, 'r', encoding='utf-8') as f:
    html_content = f.read()
html_bytes = html_content.encode()
if len(html_bytes) > 5 * 1024 * 1024:
    st.warning(
        "This HTML file is large (>5MB) and may not open "
        "correctly in all browsers via the link below."
    )
html_b64 = base64.b64encode(html_bytes).decode()
st.link_button("Open in browser", f"data:text/html;base64,{html_b64}")

Note: Interactive network plots (component_type: plot, plot_type: interactive_network) are unaffected — they continue to use st.components.v1.html().