Search notebook: error toast appears behind synthesis modal on API failure

[seanthimons]

Source: PR #156 review (round 1, item 2)

Problem

In R/mod_search_notebook.R, when a synthesis preset (overview, conclusions, research questions) hits an API error, show_error_toast() fires while the synthesis modal is still open. The toast renders behind/under the modal, and the modal briefly shows "Processing response..." before removeModal() runs a few lines later.

Affected lines: ~3320-3342, 3374-3384, 3426-3436.

Suggested Fix

Either:

• Call removeModal() before show_error_toast() inside the error handler
• Restructure to use tryCatch(finally = removeModal()) so the modal is always removed first

Context

The document notebook (mod_document_notebook.R) doesn't have this issue because its error handler is simpler (sprintf("Error: %s", e$message)) and doesn't call show_error_toast().