background_startup

Startup work that must not block activation is coordinated by `scheduleBackgroundStartup` in main.ts.
- first_paint_startup gates index discovery and sync when the Context view opens; a three-second fallback preserves warm startup when the sidebar remains closed.
- The language client starts after the same paint signal when the Context view opens, with a one-second fallback so language features still start when the sidebar remains closed.
- Registers attribute and name catalog sync once the language client exists; the initial push covers an already-ready index and the catalog-update subscription covers indexes that become ready afterwards.
Index and language-client failures are logged and do not affect the already-available UI.

Interactive page: background_startup