Disable TOC sidebar on Interactive Explorer (fixes #127) (#128)

Quarto's auto-generated #quarto-margin-sidebar (the right-hand
"On this page" TOC column) was overlapping .side-panel and silently
intercepting clicks on the Source filter checkboxes. The checkbox
would appear visible and cursor over it would appear clickable, but
mouse clicks hit the margin-sidebar first (higher in the stacking
context) and were swallowed — no toggle, no globe re-query.

Diagnosed live via Chrome DevTools:
- document.elementsFromPoint at SESAR checkbox center returned
  #quarto-margin-sidebar as the topmost element
- Installing capture-phase listeners on #sourceFilter and issuing a
  real mouse click logged zero events
- Setting pointer-events: none on the margin sidebar restored
  expected behavior

This page is an app, not an article — a TOC column adds nothing and
is actively harmful. Set toc: false in frontmatter to stop Quarto
from rendering the margin sidebar entirely.

Verified post-render: #quarto-margin-sidebar and #TOC both absent
from docs/tutorials/progressive_globe.html, still present on other
pages.

Follow-up (separate PR): audit isamples_explorer.qmd and
zenodo_isamples_analysis.qmd for the same overlap — both are tutorials
with side panels and both currently have toc: true.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

Author: rdhyee

tutorials/progressive_globe.qmd

@@ -3,6 +3,10 @@ title: "Interactive Explorer"
 subtitle: "Search and explore 6.7 million material samples"
 categories: [parquet, spatial, h3, performance, isamples]
 sidebar: false
+# No TOC: this page is an app, not an article. The right-hand TOC sidebar
+# (#quarto-margin-sidebar) was overlapping .side-panel and silently
+# intercepting clicks on the Source filter checkboxes — see issue #127.
+toc: false
 format:
   html:
     include-in-header: