performance

Sidebar webviews share the same constraints as webview_threading.
- The HTML / Svelte shell paints before index discovery begins; the post-paint `ready` handshake starts indexing.
- Keep sql. js outside the activation-critical host bundle and load it only when a database opens.
- Default neighbourhood slices; never load the full workspace graph into a pane.
- Debounce editor selection and cursor events before rebuilding slices.
- Lazy-mount cytoscape only for visible sub-panes; destroy when collapsed or hidden.
- Reuse local_graph_analysis and graph query builders rather than ad-hoc index walks in the webview.

Status: done

Interactive page: performance